Question

When 20 cal of heat is supplied to a system,
the increase in internal energy is 50 J. If
the external work done is 35 J, themechanical equivalent of heat is
1) 4.25J/cal 2) 1.26J/cal
3) 4.92 J/cal 4) 2.1 J/cal​

Answer 1

Explanation:

J = mechanical equivalent

as per 1st law of thermodynamics

Q*J= (∆u + w)

J = (35 + 50)/20 = 4.25 J/cal