A geyser of 2 kW heats water. Time to raise temperature of 5 kg water from 30°C to 50°C (specific heat 4200 J/kg°C) is MCQ with Answer and Explanation

Explanation:
F = ma, defines force quantitatively. First law inertia, third action-reaction.

Explanation:
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.

Explanation:
For a body at rest, displacement remains constant over time. The displacement-time graph is a horizontal line, parallel to time axis, indicating zero slope (velocity = 0). Option A indicates constant velocity. Option B (velocity-time zero slope) means constant velocity, not necessarily rest (could be constant non-zero velocity). Option D indicates acceleration. So C is correct.