The current in a 960 W, 240 V heater operated at 200 V is
(A) 0.25 A
(B) 0.3 A
(C) 2.5 A
(D) 3.33 A
Ans:(B) 0.3 A
Explanation :
Here Voltage V= 240
Power P = 960 W
Operated Voltage = 200
Current I = ?
Resistance R = V2/P
= (240)2/960
= 57600/960
= 60 Ohm
Current I = Applied Voltage / Resistance
= 200/60
= 3.33 A
The power rating of a motor drawing a current of 40 A at 400V is
(A) 16000 W
(B) 400 W
(C) 10 W
(D) 0.1 W
Ans: (A) 16000 W
Explanation :
Here Current I = 40 V
Voltage V= 400
Power ratting P = ?
Power = Voltage * Current
= 400 * 40
= 16000 W
so Here the rating of Motor is 16000 W.
