A car's speedometer measures: MCQ with Answer and Explanation

Explanation:
f = v/λ = 340/1.7 = 200 Hz.

Explanation:
The volume of a sphere is given by V = (4/3)πr³. The formula for relative error in volume is (ΔV/V) = 3 × (Δr/r). Since the percentage error in radius (Δr/r × 100) is 2%, the percentage error in volume will be 3 × 2% = 6%. Constants like 4/3 and π do not contribute to the error.

Explanation:
A refrigerator is a heat pump operating in reverse. A compressor squeezes the refrigerant gas, raising its temperature. As it passes through coils on the back (condenser), it releases heat and condenses into a liquid. This liquid expands through a valve, cooling rapidly, and flows into the evaporator coils inside the fridge, where it absorbs heat from the food and evaporates back into a gas.