Question

When a 60w 220v bulb and a 100w 220v bulb are connected in series then which bulb will glow brighter?

Answer 1

$\huge\bold{POWER}$

Power is the rate of doing work.

$\large\bold{For \: Question }$

$\large{For \: 1st \: bulb}$

Power p = 60 W

Potential difference V = 220 v

Resistance = ?

Since we know,

$\LARGE \boxed{Power = \dfrac{(Potential \: difference)^{2}}{Resistance }}$

$\huge\boxed{P = \dfrac{(V)^{2}}{R }}$

On placing values,

$\mathsf{60 = \dfrac{(220)^{2}}{R }}$

$\mathsf{R = \dfrac{220 \times 220}{60 }}$

$\mathsf{R = 806.6 \: ohm}$

$\large{For \: 2nd \: bulb}$

Power p = 100 W

Potential difference V = 220 v

Resistance = ?

Since we know,

$\LARGE \boxed{Power = \dfrac{(Potential \: difference)^{2}}{Resistance }}$

$\huge\boxed{P = \dfrac{(V)^{2}}{R }}$

On placing values,

$\mathsf{ 100= \dfrac{(220)^{2}}{R }}$

$\mathsf{R = \dfrac{220 \times 220}{100}}$

$\mathsf{R = 484 \: ohm}$

Since, the resistance for second bulb is less therefore more current will flow and hence, it will glow brightly.

So, the bulb with $\large{100 \: W and \: 220 \:V \: will \: glow \: brightly }$