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Choose the correct answer for the following sentences and give the
reason for your answer.(10 marks)
(i) The product of power into focal length for a lens is equal to
(ii)
(a) One (b) ten
(c) one hundred
The human eye has a lens of focal length +5 cm. The power of the
eye is
(a) 0.05 D
(b) 5 D
(c) 20 D
A transparent rod in which successive total internal reflection can
occur is called
(a) A light pipe (b) a thin prism (c) total internal
reflection
The wavelength of visible light is between
(a) 400 nm to 700 nm (b) 40 km and 70 km (c) 20 mm to 200
(iv)
mm
(v)
The SI unit for wave intensity is
(a) Js
(b) Wm?
-1
(c) Wmk1

Answers

Answer 1

Answer:

Explanation:

   


Related Questions

the spot directly above the focus on the surface of the earth​

Answers

Answer:

Epicenter

Explanation:

-The hypocenter is the point within the earth where an earthquake rupture starts. The epicenter is the point directly above it at the surface of the Earth. Also commonly termed the focus.

-The location below the earth's surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter. Sometimes an earthquake has foreshocks.

Witch of these units is NOT used to measure speed? m/s, km/h, mph, km​

Answers

Answer:

km

Explanation:

Answer:

Km

Explanation:

Speed is measured is distance traveled/time


11. Which has the greater acceleration: a car that increases its speed from 50 km/h to 60 km/h, or a bike that
goes from 0 km/h to 10 km/h in the same time? Explain.


Answers

Answer:

they are the same

Explanation:

change in speed is 10km/h for both, and the time is the same for both. they have the same acceleration.

help me please!!!!!..............

Answers

Answer:

The car took 3 hours to travel 180 miles

Explanation:

Constant Speed Motion

An object travels at constant speed if the ratio of the distance traveled by the time taken is constant.

Expressed in a simple equation, we have:

[tex]\displaystyle v=\frac{d}{t}[/tex]

Where  

v = Speed of the object

d = Distance traveled

t = Time taken to travel d.

From the equation above, we can solve for t:

[tex]\displaystyle t=\frac{d}{v}[/tex]

The car travels at v=60 mi/h for a distance of d=180 miles. The time taken is:

[tex]\displaystyle t=\frac{180\ mi}{60\ mi/h}[/tex]

t = 3 hours

The car took 3 hours to travel 180 miles

A 1.0 kg ball is thrown into the air with an initial velocity of 30 m/s. What is the kinetic energy of the ball?

Answers

Answer:

If this helps, to work out the kinetic energy the formula is K (stands for kinetic energy) = 1/2 (half of) mass and velocity. So the answer is 450 joules.

Explanation:

can a plane mirror firm a real image ? if yes tell me how ?​

Answers

Answer:

Explanation:

A plane mirror will produce a virtual image of a real object. But it is correct that a plane mirror will also produce a real image of a virtual object.A virtual image An image in a mirror is a virtual object, which can in turn be used to create another image. This can occur when you have more than one optical element in the optical system. Then the object of one component becomes the image of the next optical component.

So the answer is Yes it will!!!!

Answer:

I think u know the answer of this question

Select the correct answer. The rules of volleyball today have been only slightly changed from the rules when the game was A True B. False Next​

Answers

B bbbbb bbbbbbbbbbbbbb bbbbbbbbbbbbbbbbbbbbb

Katrina pushes off a flat sidewalk on her new skateboard.
What causes her to move?
O A. The force of her push overcomes the forces of gravity and friction
OB. The force of gravity overcomes the forces of her push and friction
o C. The force of friction overcomes the normal force of the skateboard and the force of gravity.
o D. The normal force of the skateboard overcomes the force of her push and the force of gravity

Answers

Answer:

The force of her push overcomes the forces of gravity

Explanation:

The force of her push overcomes the forces of gravity and friction. The correct option is A.

What is friction?

Friction is basically the force that restricts solid surfaces, fluid layers, and material elements from sliding against each other.

There are various kinds of friction: Dry friction is the force that opposes the relative lateral motion of two in contact solid surfaces.

Friction is defined as the force that opposes the movement of one solid object over another. Friction is classified into four types: static friction, sliding friction, rolling friction, and fluid friction.

Gravity causes objects to accelerate as they fall to the ground. Acceleration is a change in velocity, which is a measurement of the speed and direction of motion.

Katrina pushes her new skateboard off a flat sidewalk. Her push overcomes the forces of gravity and friction.

Thus, the correct option is A.

For more details regarding friction, visit:

https://brainly.com/question/13000653

#SPJ2

Periodic waves with a wavelength of 0.50 meter move with a speed of 0.30 meter in medium A. When the waves enter medium B, they travel at 0.15 meter per second. Calculate the wavelength of the waves in medium B.

Answers

Answer:

0.25 m

Explanation:

Refraction occurs when the velocity or wavelength of a wave changes at the interface between two media.

We know that refractive index=

Wavelength in medium A/wavelength in medium B = velocity in medium A/velocity in medium B

Let the wavelength of medium B be a

0.5/a = 0.3/0.15

0.5 × 0.15 = 0.3 × a

a= 0.5 × 0.15/0.3

a= 0.25 m

Scenario: The light bulb from the projector went out and the teacher was in the hallway. One student begins pressing buttons on the projector to fix it.

Questions to answer:

1. Was consent given (yes, no, unsure)?

2. What evidence do you have to prove your way of thinking?

3. How can you change the scenario to show that consent was given?

Answers

Answer:

1:No

2:The teacher was in the hall  so how would the child ask?

3: The child could have went into the hallway and asked the teacher if they could try and fix it.

Explanation:

Sorry if that isn't what your asking!

      </3 PureBeauty

Answer:

During lunch your friend asked you to come over after school, so you get on their bus to go home.

Questions to answer:

1. Was consent given (yes, no, unsure)?

2. What evidence do you have to prove your way of thinking?

3. How can you change the scenario to show that consent was given?

Explanation:1:No2:The teacher was in the hall so how would the child ask?3: The child could have gone into the hallway and asked the teacher if they could try and fix it.

Calculate the magnitude and direction of a vector whose x and y components are given
to be 30 and 40 units respectively.

Answers

Answer:

Magnitude = 50 units

Direction = 53.13°

Explanation:

The formula to find out the magnitude of a resultant vector with the help of its x and y components is given as follows:

[tex]Magnitude = \sqrt{x^{2} + y^{2}}\\\\[/tex]

where,

x = 30 units

y = 40 units

Therefore,

[tex]Magnitude = \sqrt{(30 unit)^{2} + (40\ unit)^{2}}\\\\[/tex]

Magnitude = 50 units

Now, the direction of the resultant vector will be given by the following formula:

[tex]Direction = tan^{-1}\frac{y}{x}\\\\Direction = tan^{-1}\frac{40}{30}[/tex]

Direction = 53.13°

Please help!!!! Will mark brainliest.

Spiderman, on a strand of web, accelerates upward at 1.3 m/s2. If spiderman has a mass of 76 kg,
what is the force in the strand of webbing?

Answers

Answer:

Approximately [tex]8.4 \times 10^{2}\; \rm N[/tex], assuming that [tex]g = 9.8\; \rm m \cdot s^{-2}[/tex].

Explanation:

Let [tex]m[/tex] and [tex]a[/tex] denote the mass and acceleration of Spiderman, respectively.

There are two forces on Spiderman:

Downward gravitational attraction from the earth: [tex]W = m \cdot g[/tex].Upward tension force from the strand of web [tex]F(\text{tension})[/tex].

The directions of these two forces are exactly opposite of one another. Besides, because Spiderman is accelerating upwards, the magnitude of [tex]F(\text{tension})[/tex] (which points upwards) should be greater than that of [tex]W[/tex] (which points downwards towards the ground.)

Subtract the smaller force from the larger one to find the net force on Spiderman:

[tex](\text{Net Force}) = F(\text{tension}) - W[/tex].

On the other hand, apply Newton's Second Law of motion to find the value of the net force on Spiderman:

[tex](\text{Net Force}) = m \cdot a[/tex].

Combine these two equations to get:

[tex]m \cdot a = (\text{Net Force}) = F(\text{tension}) - W[/tex].

Therefore:

[tex]\begin{aligned}& F(\text{tension})\\ &= m \cdot a + W \\ &= m \cdot (a + g)\\ &= 76\; \rm kg \times \left(1.3\; \rm m \cdot s^{-2} + 9.8\; \rm m \cdot s^{-2}\right)\\ &\approx 8.4\times 10^{2}\; \rm N\end{aligned}[/tex].

By Newton's Third Law of motion, Spiderman would exert a force of the same size on the strand of web. Hence, the size of the force in the strand of the web should be approximately [tex]8.4\times 10^{2}\; \rm N[/tex] (downwards.)

Bert is playing on his school's basketball team and one of the players on the other team continues to push him off balance when the referee isn't looking. Bert is getting frustrated as the other player is beating him to the ball almost every time by using this illegal tactic. How should Bert handle this situation in a responsible manner?

Refuse to shake hands with the other team at the end of the game and call them all dirty players
Take a flop and fall down purposely the next time the player does it to get the ref's attention
Talk to his team captain and ask him to alert the referee to keep a better eye on the player
When the ref isn't looking push the other player off balance when he has the opportunity

Answers

Answer:

Talk to his team captain and ask him to alert the referee to keep a better eye on the player.

Answer:

C - talk to coach and ask to alert the ref

Explanation:

I took the test

Potential energy due to an objects compression or extension is called ______ potential energy

Answers

Answer:

elastic potential energy

Answer:

elastic potential energy

Explanation:

mark me as brainlest

Someone please help me

What is an isotope? (2 points)

Group of answer choices

Atoms of different elements that have different numbers of neutrons

Atoms of different elements that have different numbers of protons

Atoms of the same element that have different numbers of neutrons

Atoms of the same element that have different numbers of protons

Answers

the answer is C


**because i said so-

Answer:

The answer is C.) Atoms of the same element that have different numbers of neutrons.

Explanation:

I know this is right because i took the test!

The answers plz....................

Answers

Answer:

The answer would be D

Explanation:

It's quite simple, the Universal Law of Gravitation states that all mass no matter the size, shape, or weight acts equally upon the force of gravity of the gravitational object. Basically, between all sizes, shapes, weights of masses, gravity applies the same gravitational force with all. Gravity with friction would be something else, which is also states in the Theory of Gravitation.

3.A carnival ride has a radius of 5.00 m and exerts an applied force of 987 N on an 80 kg rider.
a. Find the centripetal acceleration of the rider.
Given:
r =
F =
m =
Unknown:

a =?

Equation:

a = F / m

Answers

Answer:

gggn×2

lol

Explanation:

hujhyhhhgyhngfg

ojui

ukk

lol

What type of device is a refrigerator?
A. A heat pump that uses work to move heat
B. A heat pump that uses heat to do work
C. A heat engine that uses work to move heat
D. A heat engine that uses heat to do work

Answers

A heat pump that uses work to move heat

Bob who has a mass of 100 kg stands ona. Frictionless frozen lake with a 20 kg rock in his hands. He throws the rock forward with a velocity of +5 m/s. What is the velocity of bob after he throws the rock

A. -2 m/s
B. -1 m/s
C. 0 m/s
D. 1 m/s

Answers

Answer:

Option B

Explanation:

This involves the conservation of momentum:

m1v1 = m2v2

Now initially neither the rock nor Bob is moving. Then the rock moves forward with a velocity of 5 m/s, having a mass of 20 kg. But Bob moves back by the conservation of momentum, so at what velocity?

0 = 20(5) + 100(vf),

-100 = 100vf,

vf = - 1m/s

When your body takes in food, what type of energy does it get from the food?

Answers

Answer: Chemical Energy

Explanation:

Glucose and other food molecules are broken down by controlled stepwise oxidation to provide chemical energy in the form of ATP and NADH.

Some of the types of energy in the electromagnetic spectrum will be familiar, such as X-rays, microwaves, and radio waves. The most important part of the spectrum in photosynthesis is visible light. What are the colors of the visible spectrum

Answers

Answer:

Red, orange, yellow, green, cyan, blue, violet.

Explanation:

As we know that the energy of every photon of light directly depends on the size of the wavelength. As short as the wavelength would be as greater the energy delivered by each photon of light would be. Thus, the colors displayed in the visible electromagnetic spectrum would include 'red, orange, yellow, green, cyan, blue, violet' with different wavelengths.

How is the weight formula similar to the force formula? W=mg and F=ma*
1.They both have mass in them
2.They both have acceleration
3.Gravity causes acceleration
4.All of the above
5.None of the above

Answers

It is number 2 lolololol

While riding her bike, Ms. Parker average a velocity of 20m/s. If she maintains that velocity for a time of 20 seconds, how far does she rides?

Answers

Answer:

400 m

Explanation:

20m/s x 20s = 400m

A 0.061 kg golf ball is struck by a golf club with a force of 299.4 N. The change in velocity of the ball is 54.3 m/s. How much time is the ball in contact with the club?​

Answers

Answer:

The time the ball is in contact with the club is approximately 0.011063 seconds

Explanation:

The question is with regards to Newton's second law of motion which states that a force is equal to the rate of change of momentum produced

The given parameters are;

The mass of the ball, m = 0.061 kg

The force with which the ball is struck with the golf club, F = 299.4 N

The change in velocity of the ball, Δv = 54.3 m/s

By Newton's second law, we have;

[tex]F_{net} = \dfrac{\Delta P}{\Delta t} = \dfrac{m \times \Delta v}{\Delta t}[/tex]

Where;

Δt = The time it takes the momentum of the object to change = The time the ball is in contact with the club

Substituting the known values, we get;

[tex]F_{net} = F =299.4 = \dfrac{0.061 \times 54.3}{\Delta t}[/tex]

[tex]\therefore \Delta t = \dfrac{0.061 \times 54.3}{299.4} \approx 0.011063[/tex]

The time the ball is in contact with the club = Δt ≈ 0.011063 seconds.

A boy is pulling a box on the ground by a string to the right. What four forces he using?

Answers

The strong force in his body

A total charge of 7.5 mC passes through a cross-sectional area of a wire in 0.9 s. What is the current in the wire

Answers

Answer:

the  current in the wire is  0.008333333  A

Explanation:

The computation of the current in the wire is as follows;

Current in the wire is

= Total charge ÷ cross sectional area of the wire

= 7.5 × 10^-3C ÷ 0.9s

= 0.008333333  A

Hence, the  current in the wire is  0.008333333  A

We simply applied the above formula so that the correct current of the wire could come

And, the same is considerd and relevant too

Comparing the reactants and the products of a chemical reaction, which observation can best be used to argue that the reaction is endothermic?(1 point)

The volume of the reactants is greater than the volume of the products.

The total energy of the reactants is equal to the total energy of the products.

There are fewer chemical bonds in the reactants than there are chemical bonds in the products.

The temperature of the reactants is greater than the temperature of the products.

Answers

Answer:

D) The temperature of the reactants is greater than the temperature of the products.

Explanation:

All the answers:

1. A) The reactants are unlit charcoal, and the products are charcoal that has already burned and released its energy

2. C) sugar + oxygen → carbon dioxide + water + energy

3. D)  iron + oxygen → rusted iron + energy

4. A) an endothermic reaction, because ice absorbs heat to become liquid water

5. D) The temperature of the reactants is greater than the temperature of the products.

We can argue that a reaction is endothermic when the temperature of the reactants is greater than the temperature of the products.

What is an endothermic reaction?

An endothermic reaction is a chemical reaction accompanied by the absorption of heat.

Comparing the reactants and the products of a chemical reaction, which observation can best be used to argue that the reaction is endothermic?

The volume of the reactants is greater than the volume of the products. False. There is no relation between the volume and the endothermicity.The total energy of the reactants is equal to the total energy of the products. False. If the total energy is equal, there is no heat (energy) absorption.There are fewer chemical bonds in the reactants than there are chemical bonds in the products. False. We must consider not only the number of bonds, but also their energies, to establish if a reaction is endothermic.The temperature of the reactants is greater than the temperature of the products. True. If the reaction is endothermic and absorbs heat from the surroundings, the temperature of the reactants will be greater than the temperature of the products.

We can argue that a reaction is endothermic when the temperature of the reactants is greater than the temperature of the products.

Learn more about endothermic reactions here: https://brainly.com/question/1995950

WILL REWARD ASAP Calculate the density of a 25g stone that causes water in a graduated cylinder to
go up by 12.5 ml.

Answers

5g sorry if wrong let know if it is I’ll correct it

A skier is moving at a constant velocity for 20 seconds when he hits a downhill slope of 60 meters and begins to accelerate at 6 m/s^2 for 6 seconds. At the bottom of the hill he begins to stop over 10 seconds
a. What was the skiers constant velocity before going down hill?
b. What was the skier’s acceleration as he comes to a stop?
c. What was the skier’s total distance over the 36 seconds?
d. What was the skier’s average speed during the 36 seconds?

Answers

I think the answer is c.

Can a molecule of DNA contain 60% thymine? Why
or why not?

Answers

Answer:

The possibility of Adenine=40% and Thymine=60% is only in single stranded DNA molecule. In the question, the DNA sample referred is a single stranded DNA. If guanine=10% as guanine will always pair with cytosine, i.e.cytosine is also 10% then adenine and thymine accounts 80% as adenine will always pair with thymine.

A molecule of DNA cannot contain 60% thymine because this amount will surpass 100% in consideration of its complementary base.

DNA:

DNA or deoxyribonucleic acid is a biological molecule that stores genetic information in living cells.

DNA is a double stranded molecule that consists of nucleotide bases as follows:

AdenineThymine GuanineCytosine

According to Chargaff in his rule, the amount of adenine & thymine and guanine & cytosine in a DNA molecule is the same, which must equal 100% overall.

Therefore, if thymine is 60% in the DNA, adenine will also be 60%, which in total has already surpassed 100% without adding the other two bases.

Learn more about DNA at: https://brainly.com/question/1822938

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