Physics Past Questions and Answers

A blacksmith heated a metal whose cubic expansivity is 6.3 x 10^-6K^-1. The areal expansivity is

The ratio of the coefficient of linear expansion of two metals ^∝₁/_∝[sub]2[/sub] is 3:4. If, when heated through the same temperature change, the ratio of the increase in length of the two metals, ^e₁/_e[sub]2[/sub] is 1:2, the ratio of the original lengths ^l₁/_l[sub]2[/sub] is

The fundamental frequency of a plucked wire under a tension of 400N is 250Hz. When the frequency is changed to 500 Hz at constant length, the tension is

Three cells each of e.m.f 1.5 V and internal resistance 2.5Ω are connected as shown in the diagram above. Find the net e.m.f and the internal resistance

In the diagram above , if the magnetic field points into the paper and the force on a current - carrying conductor points upwards, what is the direction of the current?