Introduction to Light

Q.

What are non luminous objects?

Q.

What is light energy and its uses?

Q.

What is the major function of aqueous humour?

1. It prevents dispersion of light.

2. It filters the light that is going in to form the image.

3. It is present to maintain the pressure inside.

4. It reflects light.

Q.

What do you mean by the refractive index of a medium?

1. A medium in which light travel with high speed

2. None of these

3. A medium in which light travel with low speed

4. A medium in which light travel with variable speed, but the speed will depend on medium to medium

Q.

Why can't we see in the dark?

1. because eyes don't work in dark

2. because there is no light to reflect from the objects

3. both A & B

4. power of eye is reduced

Q.

What do you mean by a parallel beam of light?

Q. We don’t see any objects when it is dark. Give reason

Q.

What is the function of the iris in the human eye?

1. Iris restricts the light to pass through the eye over to the retina.

2. Iris provides protection to the eye from microorganisms.

3. Iris controls the size of the pupil and hence the amount of light entering the eye.

4. Iris allows color detection in the eye.

Q.

Can energy be converted into Mass ?

Q. what is photon?

Q. Is light solid, liquid or gas?

Q.

What is the formula for refractive index?

1. None of these

2. n =

3. n =
   
4. n =

Q.

X-ray travel faster than visible light.

1. True
2. False

Q. Is light a ray or a wave ?

Q.

If the speed of light in air is 3 $\times$${10}^8$ m/s and speed of light in water is reduced by a factor of 1.3 when compared with that of the speed of light in air. Find out the speed of light in water?

1. $2.25\times$​​ ${10}^{8}m{s}^{-1}$

2. $330m{s}^{-1}$

3. $3\times$​​ ${10}^{8}m{s}^{-1}$

4. $1.6\times$​​ ${10}^{8}m{s}^{-1}$

Q.

Light travels with the same speed in different media.

1. f = 2R

2. f = R

Q.

How do our eyes perceive that the colour of banana is yellow?

Q.

In nuclear fission, when a nucleus splits into two, the mass of the original nucleus is equal to the total mass of the two nuclei.

1. False

2. True

Q.

Encircle the odd one out and give reasons for your choice.

Heat, light, sound, moon, electricity

Q.

What are the consequences of rectilinear propagation of light?

Q. 3×10^8 is speed of light in vacum or in air because we studied that it is speed of light in air

Q.

A stone is dropped in a well of depth 500 m and a sound is heard after 45/4 seconds. Then speed of sound is (if g= 10 m/s): x* 100 m/s. Find the value of x.

Q.

Give one word for:

A broad collection of light rays.

Q. If an object do not reflect light it is not visible to us. Is there any object do not reflect light ? If YES no matter if it is right in front of me it will not be visible.

Q.

What is the origin or source of Visible light?

Q.

Which of the following is an example of bioluminescence ?

1. Bee

2. Stars

3. Butterfly

4. Firefly

Q.

State the main function of the following:

Yellow spot

Q. A light year is the distance travelled by light in one year. How many kilometers does light travel in a year assuming speed of light is $3\times {10}^{8}m{s}^{-1}$ ?

1. 9.56 trillion kilometers
2. 9.46 trillion kilometers
3. 9.36 trillion kilometers
4. 9.26 trillion kilometers

Q.

Which of the following are true regarding light?

1. It is a form of energy

2. It makes things around us visible

3. A ray of light travels in a straight line

4. Light has mass

Q.

The beam of light coming from the headlight of a car is a:

1. convergent beam

2. divergent beam

3. parallel beam

4. none of the above