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Four identical electrical lamps are labe...

Four identical electrical lamps are labelled `1.5 V`, `0.5 A` which describes the condition necessary for them to operate at normal brightness. A `12 V` battery of negligible internal resistance is connected to lamps as shown, then

A

The value of R for normal brightness of each lamp is `(3//4) Omega`

B

The value of R for normal brightness of each lamp is `(21//4) Omega`

C

Total power dissipated in circuit when all lamps are normally bright is 24 W

D

Power dissipated in R is 21W when all lamps are normally bright

Text Solution

Verified by Experts

The correct Answer is:
B, D
Main current I =2A
Voltage = 1.5 V
Now, `V_(R) = 12-1.5=10.5 V`
Power dissipated `=(10.5)^(2)/(21.4) = 21 W`
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