Question

When three identical bulbs of 60 watt, 200 volt rating are connected in series to a 200 volt supply, the power drawn by them will be :-

Answer 1

Please find the answer in the attachment.

Answer 2

Answer:

20W.

Explanation:

Bulb Watt = 60 (Given)

Voltage of the bulb = 200V (Given)

Supply series = 200 (Given)

Resistance of each bulb = (V²/P)

= (200²/60)

= 666.67 ohms.  

When three bulbs are connected in series their resultant resistance -

Current flowing through 3 in series I = (E/R) = 200/(3 x 666.7) = 0.1A.  

Thus, the power drawn by bulb when connected across 200 V supply -

Power each bulb dissipates = (200/3) x 0.1

= 6.67 Watts.  

By all 3 bulbs = 20W

Thus, the power drawn by three bulbs will be 20W.