Question 361: Current Electricity

Question

Two electric bulbs, rated at (25 W, 220 V) and (100 W, 220 V), are connected in series across a 220 V voltage source. If the 25 W and 100 W bulbs draw powers P
1
and P
2
respectively, then :

Accepted Answer

$${R_1} = {{{{220}^2}} \over {25}}$$
$${R_2} = {{{{220}^2}} \over {100}}$$
$$L = {{220} \over {{R_1} + {R_2}}}$$
$${P_1} = {i^2}\,{R_1}$$
$${P_2} = {i^2}\,\,({R_2}\, = \,4W)$$
$$ = {{{{220}^2}} \over {\left( {{{{{220}^2}} \over {25}} + {{{{220}^2}} \over {100}}} ight)}} 	imes {{{{220}^2}} \over {25}}$$
$$ = {{400} \over {25}} = 16W$$

Answer

P
1
= 4W, P
2
= 16 W

Answer

P
1
= 16W, P
2
= 4 W

Answer

P
1
= 9W, P
2
= 16 W

Answer

P
1
= 16W, P
2
= 9 W

Current Electricity

Two electric bulbs, rated at (25 W, 220 V) and (100 W, 220 V), are connected in series across a 220 V voltage source. If the 25 W and 100 W bulbs draw powers P 1 and P 2 respectively, then :

Choose the correct answer: