An ideal gas is enclosed in a cylinder fitted with a frictionless, movable piston of area 0.04 m ^2 . The gas is heated by an electrical coil of resistance 50 carrying a current of 2 A for 10 s . During this process, the gas expands at a constant pressure of 10^5 Pa and its internal energy increases by 1200 J . The distance moved by the piston is:

Step-by-step solution

Heat supplied by the electrical coil is given by Joule's law of heating: Q = I^2 R t Q = (2)^2 50 10 = 2000 J According to the first law of thermodynamics: Q = U + W 2000 = 1200 + W W = 800 J Work done by the gas at constant pressure is: W = P V = P A d Substituting the given values: 800 = 10^5 0.04 d 800 = 4000 d d = 800 4000 = 0.2 m d = 20 cm Answer: 20 cm