The device used for detecting and measuring small electric current is MCQ with Answer and Explanation

Explanation:
v_esc ∝ √(1/R). If R→R/4, v_esc ∝ √(4) = 2. So 2v_e.

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.

Explanation:
A geostationary satellite orbits the Earth directly over the equator at an altitude of ~35,786 km. It revolves in the same direction the Earth rotates. Its orbital period perfectly matches Earth's rotational period, which is 24 hours. Because of this, it appears entirely stationary from any point on Earth's surface, making it ideal for communications and DTH TV.