EmSAT EmSAT Physics 4

Question 1

What is the speed of light in a vacuum?

Accepted Answer

3 × 10⁸ m/s

Answer

The speed of light in a vacuum is approximately 3 × 10⁸ m/s (300,000 km/s). This is a fundamental constant of nature denoted by c.

Question 2

What type of wave is sound?

Accepted Answer

Longitudinal wave

Answer

Sound is a longitudinal (mechanical) wave where particles vibrate parallel to the direction of wave propagation. It requires a medium (solid, liquid, or gas) to travel.

Question 3

What happens to the frequency of a wave when its wavelength decreases (speed constant)?

Accepted Answer

Frequency increases

Answer

Wave speed = frequency × wavelength (v = fλ). If speed is constant and wavelength decreases, frequency must increase to maintain the equation.

Question 4

What is the Doppler effect?

Accepted Answer

Change in observed frequency due to relative motion

Answer

The Doppler effect is the change in observed frequency of a wave due to the relative motion between the source and the observer. A siren sounds higher as it approaches and lower as it moves away.

Question 5

Which type of electromagnetic wave has the highest frequency?

Accepted Answer

Gamma rays

Answer

Gamma rays have the highest frequency (and shortest wavelength) in the electromagnetic spectrum. They are produced by nuclear reactions and have the most energy.

EmSAT Practice Test

EmSAT Practice Test

EmSAT EmSAT Physics 4