The scientist who invented the telephone was MCQ with Answer and Explanation

Explanation:
A Venturimeter consists of a converging pipe, a narrow throat, and a diverging pipe. As fluid passes through the constricted throat, its velocity increases. According to Bernoulli's principle, this increase in kinetic energy must be accompanied by a strictly corresponding decrease in fluid pressure. By measuring this pressure difference, the flow rate can be precisely calculated.

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:
Superconductivity occurs in certain materials below a critical temperature T_c, where electrical resistance drops abruptly to zero, and magnetic fields are expelled (Meissner effect). Option B describes insulators; C and D are unrelated. Memory aid: 'Superconductor: R=0 below T_c; perfect diamagnetism'. This modern physics concept is frequently tested in competitive exams. Always distinguish superconductivity (zero resistance) from perfect conductivity (theoretical limit); real superconductors exhibit Meissner effect, a defining property.