Introduction to Light

Q.

How does the moon shine?

Q.

Light travels in ___________.

1. a curved path

2. a straight line

3. a circular path

4. a zig-zag path

Q.

Calculate the refractive index of the material of a glass slab. Given that the speed of light through the glass slab is $2\times {10}^8\mathrm{m}/\mathrm{s}$ and in air is $3\times {10}^8\mathrm{m}/\mathrm{s}$.

Q. Statement 1: Angle of incidence is greater than the angle of refraction.
Statement 2: Angle of incidence is lesser than the angle of refraction.
Statement 3: Angle of emergence is equal to the angle of incidence.
Which of the following is/are correct with respect to refraction in a glass slab?

1. Statements 2 and 3 are false, but statement 1 is true.
2. Statements 1 and 3 are true, but statement 2 is false.
3. Statements 1 and 3 are false, but statement 2 is true.
4. Statements 2 and 3 are true, but statement 1 is false.

Q.

An invisible energy which causes us the sensation of sight is called _______ energy.

Q.

____________ is a phenomenon which happens when a ray of light passes from one transparent medium to another.

Q. Which of the following is/are the characteristic(s) of light?

1. 
   Rectilinear propagation
   
2. Reflection
3. Refraction
4. All of the above

Q.

A person cannot see distinctly objects kept beyond$2m$. This defect can be corrected by using a lens of power

1. + 0.5 D

2. – 0.5 D

3. + 0.2 D

4. – 0.2 D

Q.

The flame of a gas stove is________

1. luminous

2. non-luminous

3. opaque

4. transparent

Q. On which of the following reflecting surfaces will diffused reflection take place?

1. Plane mirror
2. Polished marble floor
3. Wooden table
4. Chalk powder

Q. The refractive index of glass is 1.5. What does it mean?
(Note : $c$ is the velocity of light in vacuum, $v_g$ is the velocity of light in glass.)

1. $\frac{v_g}{c}=1.5$
2. $\frac{c}{v_g}=1.5$
3. $c=1.5$
4. $v_g=1.5$

Q.

A ray of light is reflected by the pole of a concave mirror at an angle of 80^o. The angle of incidence will be.

1. 80^o

2. 180^o

3. 0^o

4. 50^o

Q. Which of the following images represent the refraction of light?

1. 
2. 
3. 
4. 

Q. What are the precautions that should be taken care of while drawing ray diagrams while two mirrors are placed parallel to each other and in the second case they are placed perpendicular to each other....??

Q. Which of the statement(s) is/are correct?

1. A is incident ray.
2. B is reflected ray.
3. C is normal ray.
4. B is normal ray.

Q.

A person can read at the closest distance of $50cm$. In order for him to read at $30cm$. Identify the defect, nature, and power of the lens?

Q. Light can pass through

1. Vacuum
2. Glass
3. Air
4. All of the above

Q. The laws of reflection holds good for:

1. \N
2. plane mirror only
3. concave mirror only
4. convex mirror only

Q.

For spherical mirrors

1. Both laws of reflection are valid

2. Laws of reflection are not valid

3. Only first law is valid

4. Only second law is valid

Q. A ray through the center of curvature hitting the spherical mirror, after reflection makes an angle of ____ with the normal.

1. ${45}^{\circ }$
2. ${270}^{\circ }$
3. $0^{\circ }$
4. ${90}^{\circ }$

Q.

The following question contains two statements labeled ‘A’ and ‘R’. Examine each statement carefully and decide, if the assertion ‘A’ and reason ‘R’ are individually correct. If so, decide, whether the reason R is the correct explanation of A. Select your answer, using the options given below.

A The top surface of water contained in a beaker appears silvery when held above eye level.

R It is an account of the phenomenon of total internal reflection.

1. Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’

2. Both ‘A’ and ‘R’ are correct and ‘R’ is the not correct explanation of ‘A’

3. ‘A’ is correct, but ‘R’ is incorrect.

4. ‘A’ is incorrect, but ‘R’ is correct.

Q. A person is advised to use a lens of power +2 D for correcting his vision. Identify the defect of vision, and find the focal length of the lens.

1. Myopia, $-0.5m$
2. Hypermetropia, $0.5m$
3. Hypermetropia, $-0.5m$
4. Myopia, $0.5m$