In a nuclear reactor, heavy water is used as MCQ with Answer and Explanation

In a nuclear reactor, heavy water is used as
A. Coolant
B. Fuel
C. Moderator
D. Control rod
Answer: Option C
Solution (By JKSSB Mock Tests)
Heavy water (D₂O) slows neutrons, good moderator.

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Physics Questions

Question #1
The escape velocity from a planet depends on:
A. Temperature of the planet
B. Both mass and radius of the planet
C. Radius of the planet only
D. Mass of the escaping body

Correct Answer: Option B


Explanation:
Escape velocity v_e = √(2GM/R), where M is planet mass, R its radius. Thus v_e depends on both M and R. It is independent of the escaping body's mass (as gravitational and inertial mass cancel). Memory tip: 'v_e ∝ √(M/R); larger M or smaller R ⇒ higher escape velocity'. This gravitation formula application is frequently tested in competitive exams. Always recall that escape velocity is a property of the planet, not the projectile. This problem assesses understanding of gravitational potential energy concepts.

This question belongs to: Science Physics
Question #2
What is the minimum distance required to hear a distinct echo? (Assuming speed of sound in air is 344 m/s)
A. 10 meters
B. 34.4 meters
C. 17.2 meters
D. 25.6 meters

Correct Answer: Option C


Explanation:
The human ear retains the sensation of sound for about 0.1 seconds (persistence of hearing). To hear a distinct echo, the reflected sound must reach the ear after at least 0.1 s. Distance traveled by sound = Speed × Time = 344 m/s × 0.1 s = 34.4 m. Since this is the total distance (go and return), the minimum distance to the obstacle is 34.4 / 2 = 17.2 meters.

This question belongs to: Science Physics
Question #3
Two electric bulbs rated 60W, 220V and 100W, 220V are connected strictly in series across a 220V supply. Which bulb will glow brighter?
A. Neither will glow.
B. 60W bulb
C. 100W bulb
D. Both will glow with equal brightness.

Correct Answer: Option B


Explanation:
Resistance of a bulb is R = V^2 / P. The 60W bulb has a higher resistance than the 100W bulb. When connected in series, the exact same current (I) flows through both. The power consumed (which determines brightness) is given by P = I^2R. Since the 60W bulb has higher resistance (R), it consumes more power and glows brighter.

This question belongs to: Science Physics