The number of significant figures in the measurement 0.0050200 m is: MCQ with Answer and Explanation

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:
Audible range: 20 Hz to 20,000 Hz (20 kHz). Below 20 Hz infrasound, above ultrasound. This range decreases with age. Dogs can hear higher frequencies (ultrasonic whistles).

Explanation:
Scientific notation: 3.00 has three significant figures (3,0,0). Exponent part not counted. It's a clear way to show precision. 3×10⁸ has 1, 3.0×10⁸ has 2.