In a nuclear reactor, control rods are made of materials that: MCQ with Answer and Explanation

In a nuclear reactor, control rods are made of materials that:
A. Emit neutrons
B. Absorb neutrons
C. Reflect neutrons
D. Moderate neutrons
Answer: Option B
Solution (By JKExamLibrary)
Control rods (made of cadmium, boron, or hafnium) absorb neutrons to regulate the fission chain reaction rate. Inserting rods deeper reduces neutron population, slowing reaction; withdrawing them increases reaction rate. Moderators (water, graphite) slow neutrons to thermal energies for efficient fission. Memory aid: 'Control rods = neutron absorbers; Moderators = neutron slowers'. This application question tests knowledge of reactor components, common in competitive exams. Always distinguish roles: fuel (fissionable material), moderator, control rods, coolant.

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A car travels 30 m in 2 s with uniform acceleration starting from rest. Acceleration is
A. 7.5 m/s²
B. 30 m/s²
C. 15 m/s²
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Correct Answer: Option C


Explanation:
s = ½ a t² => 30 = ½ a (4) => a = 15 m/s².

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Correct Answer: Option B


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Correct Answer: Option A


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