NSAA NSAA Physics - Waves and Optics 2

Question 1

The critical angle for a glass-air interface is 42°. What is the refractive index of the glass?

Accepted Answer

1.49

Answer

n = 1/sin(θc) = 1/sin(42°) ≈ 1/0.669 ≈ 1.49.

Question 2

Sound travels at 340 m/s. What is the wavelength of a 170 Hz sound wave?

Accepted Answer

2 m

Answer

λ = v/f = 340/170 = 2 m.

Question 3

In a transverse wave, the direction of particle vibration is:

Accepted Answer

Perpendicular to wave propagation

Answer

In transverse waves, particles vibrate perpendicular to the direction of energy transfer.

Question 4

The Doppler effect causes the observed frequency of a source moving toward an observer to be:

Accepted Answer

Higher than the emitted frequency

Answer

When the source moves toward the observer, wavefronts bunch together, increasing the observed frequency.

Question 5

Which phenomenon explains why a straw appears bent when placed in a glass of water?

Accepted Answer

Refraction

Answer

The straw appears bent due to refraction — light changes direction when moving from water to air.

NSAA - Natural Sciences Admissions Assessment Practice Test