(a) An electric bulb of resistance 500 Ω, draws a current of 0.4 A. C

1.	(a) An electric bulb of resistance 500 Ω, draws a current of 0.4 A. Calculate the power of the bulb and the potential difference at its end.(b) State two causes of energy loss in a transformer.(c) State two characteristics of a good thermionemitter. (d) State two factors upon which the rate of emission of thermions depends. (e) When does the nucleus of an atom tend to be radioactive?
Answer» (a) Given R = 500 W, I = 0.4 A, V = ?, Using V = IR, we have V = 0.4 × 500 = 200 V (b) Copper loss and iron loss. (c) (i) Should have high melting point and (ii) Should have low value of work function. (d) (i) The nature of the metal and (ii) Temperature of the metal surface. (e) The nucleus tends to be radioactive when it becomes unstable.

(a) An electric bulb of resistance 500 Ω, draws a current of 0.4 A. Calculate the power of the bulb and the potential difference at its end.(b) State two causes of energy loss in a transformer.(c) State two characteristics of a good thermionemitter. (d) State two factors upon which the rate of emission of thermions depends. (e) When does the nucleus of an atom tend to be radioactive?

Answer»

(a) Given R = 500 W, I = 0.4 A, V = ?, Using V = IR, we have V = 0.4 × 500 = 200 V

(b) Copper loss and iron loss.

(c) (i) Should have high melting point and

(ii) Should have low value of work function.

(d) (i) The nature of the metal and

(ii) Temperature of the metal surface.

(e) The nucleus tends to be radioactive when it becomes unstable.