51. The volume of 1 mole gas changes from V to 10 V in isothermal expansion, then change in entropy will be (R is gas constant) (1) R (2) 2R (3) 2.303 R (4) 4.606 R 52. The number of ways through which three fermions can be distributed in four energy levels are (1) 4 (3) 20 (2) 16 (4) 32 53. In given circuit, if source deliver maximum power to load, then load impedance must be Es Zs 120+40j (1) 120+40j (2) (3) 40+120j (4) 120-40j 1102 54. The rms value of input voltage in full wave rectifier (having two diodes) is 300 2 V. The peak inverse voltage of each of diode of rectifier will be 300 (1) 2 V (2) 300 V (3) 300 2V (4) 600 V 55. Ripple factor of a full wave rectifier using -section filter and load resistance R for f = 60 Hz, C and C in F, L in henrys and R in ohms is given as (1) 1.46 LC 0.83 (2) LC,C 3300 (3) (4) LCC2RL RL 1600 L