Physics Past Questions and Answers

The earpiece of a telephone handset converts energy from

Two identical cups containing the same volume of water at 45°C and 5°C, are left in a room at 25°C. Which of the following graphs correctly illustrates the variation of temperature with time?

A ray of light travelling from glass into ethyl alcohol is incident at the boundary at an angle of incidence 3\(^o\). Calculate the angle of refraction. [Refractive index of glass =1.5; refractive index of ethyl alcohol = 1.36]

A 60kg man stands on a weighing balance in an elevator. If the elevator accelerates upwards at 5ms\(^{-2}\), determine the reading of the scale. [g = 10ms\(^{-2}\)]

The length of an iron bar is 100cm at 20°C. At what temperature will its length increase by 0.01%? [Linear expansivity of iron = 1.2 x 10\(^{-5}\)°C]