Mdcat-past-papers - UHS Quiz

341. An observer standing near the seashore observes 54 waves per minute. If the wavelength of the water is 10 m, then the velocity of the water wave is:

540 m/s
9 m/s
5.4 m/s
None

342. Wave trough refers to the:

Highest point of wave
Lowest point of wave
Wavelength
Wave speed

343. When a wave goes from one medium to another, there is no change in the:

Frequency
Wavelength
Amplitude
Velocity

344. If transverse waves are passing through a medium, then particles of the medium:

Remain stationary
Move toward
Move away
Move in simple harmonic motion

345. In transverse waves, the portion above the mean level is called:

Wave front
Wave crest
Wave trough
Wavelength

346. Which one of the following does not cause stationary waves?

Two waves of equal frequency
Two waves of same speed
Two waves of unequal amplitude
Two waves travelling in opposite directions

347. A distant star is receding from the earth with a speed of 1.40 x 10⁷ m/s. It emits light of frequency 4.57 x 10¹⁴ Hz. The speed of light is 3 x 10⁸ m/s. The Doppler effect formula can be used with light waves. What will be the frequency of this light when detected on Earth?

2.04 x 10¹³ Hz
4.37 x 10¹⁴ Hz
4.57 x 10¹⁴ Hz
4.79 x 10¹⁴ Hz

348. A metallic wire of length 2m hooked between two points has tension 10N. If mass per unit length is 0.004kg/m, then fundamental frequency emitted by wire on vibration is:

48Hz
24Hz
12.5 Hz
6.25 Hz

349. Which one of the following is INCORRECT about the nodes when the string is plucked:

Amplitude of vibration is zero
Do not move along the string
Produced at the fixed ends of strings
Distance between consecutive nodes is 1 wavelength

350. Which one of the following does not cause stationary waves?

Two waves of equal frequency
Two waves of same speed
Two waves of unequal amplitude
Two waves travelling in opposite directions

351. Sodium line from star = 589nm, in lab = 497nm. This means the star is:

Moving away from the Earth
Moving towards the Earth
Stationary
Revolving around a planet

352. Source of sound moves towards stationary observer. Apparent frequency is:

f₀ = (v+vₛ)/v • f
f₀ = v/(v−UI) • f
f₀ = (v−Uₛ)/v • f
f₀ = (v+vₛ)/v • f

353. Observer moves at speed v toward a stationary source. Waves per second received:

f' = f(v+vₒ/v)
f' = f(v/v−vₒ)
f' = f(v+vₒ/v)
f' = f(v/v−vₒ)

354. Red shift of galaxy light shows universe is:

Expanding
Contracting
Stationary
Oscillating

355. Plane moves at 0.5v toward observer. Sound = 200Hz. What is heard?

400Hz
100Hz
120Hz
180Hz

356. Galaxy light shifts toward red end. The galaxy is:

Approaching Earth
Receding from Earth
Stationary
Approaching or stationary

357. Star recedes at 1.4×10⁷ m/s, emits 4.57×10¹⁴ Hz. Speed of light = 3×10⁸ m/s. Detected frequency?

2.04×10¹⁴ Hz
4.3×10¹⁴ Hz
4.57×10¹⁴ Hz
4.79×10¹⁴ Hz

358. Correct Doppler equation when source approaches observer (f₀ = observed freq, fₛ = source freq):

f₀ = v/(v−vₛ) • fₛ
f₀ = (v+vₛ)/v • fₛ
f₀ = (v−vₛ)/v • fₛ
f₀ = (v−vₛ)/(v+vₛ) • fₛ

359. In which of the following, the change in internal energy is more?

In the system A
In the system B
cannot be predicted
changes in both is zero (Both are cyclic)

360. If Q is the amount of heat supplied to a system and 'w' is the work done, then change in internal energy can be defined as:

Q/W
Q-W
W/Q
1 + Q/W