A 220 V , 50 Hz AC source is connected to a 25 V, 5 W lamp and an additional resistance R in series (as shown in figure) to run the lamp at its peak brightness, then the value of R (in ohm) will be .

Question

A 220 V , 50 Hz AC source is connected to a 25 V, 5 W lamp and an additional resistance R in series (as shown in figure) to run the lamp at its peak brightness, then the value of R (in ohm) will be . (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

P = Vi 5=25 i i=(1/5) VR=i R (220-25)=(1/5) R R=195 × 5=975 Ω

Q. A $220 V, 50 Hz$ AC source is connected to a $25 V, 5 W$ lamp and an additional resistance $R$ in series (as shown in figure) to run the lamp at its peak brightness, then the value of $R$ (in ohm) will be _______.

$P = Vi$
$5 = 25 i$
$i = \frac{1}{5}$
$V_{R} = i R$
$(220 - 25) = \frac{1}{5} R$
$R = 195 \times 5 = 975 Ω$

Q. A 220V,50Hz AC source is connected to a 25V,5W lamp and an additional resistance R in series (as shown in figure) to run the lamp at its peak brightness, then the value of R (in ohm) will be _______.

P=Vi 5=25i i=51​ VR​=iR (220−25)=51​R R=195×5=975Ω

Q. A $220 V, 50 Hz$ AC source is connected to a $25 V, 5 W$ lamp and an additional resistance $R$ in series (as shown in figure) to run the lamp at its peak brightness, then the value of $R$ (in ohm) will be _______.

$P = Vi$
$5 = 25 i$
$i = \frac{1}{5}$
$V_{R} = i R$
$(220 - 25) = \frac{1}{5} R$
$R = 195 \times 5 = 975 Ω$