NEET Physics 3

Question 1

When light travels from a denser medium to a rarer medium at an angle greater than the critical angle, what phenomenon occurs?

Accepted Answer

Total internal reflection

Answer

Total internal reflection occurs when light strikes the interface at an angle exceeding the critical angle while traveling from denser to rarer medium.

Question 2

A convex lens of focal length 20 cm forms a real image of an object placed 30 cm from the lens. The image distance is:

Accepted Answer

60 cm

Answer

Using lens formula 1/v − 1/u = 1/f: 1/v = 1/20 + 1/(−30) = 1/60, so v = 60 cm.

Question 3

In Young's double slit experiment, if the distance between the slits is halved and the distance to the screen is doubled, the fringe width becomes:

Accepted Answer

4 times

Answer

Fringe width β = λD/d; when d is halved and D is doubled, β becomes 4 times the original.

Question 4

The energy of a photon with wavelength λ is E. If the wavelength is doubled, the energy becomes:

Accepted Answer

E/2

Answer

Since E = hc/λ, doubling wavelength halves the energy to E/2.

Question 5

Which colour of visible light has the highest frequency?

Accepted Answer

Violet

Answer

Violet light has the shortest wavelength (~400 nm) in the visible spectrum and therefore the highest frequency.

NEET - National Eligibility cum Entrance Test Practice Test

NEET - National Eligibility cum Entrance Test Practice Test

NEET Physics 3