Q.
Two bulbs $X\ and\ Y$ having same voltage rating and of power 40 W and 60 W respectively are connected in series across a potential difference of 300 V, then
A) $X$ will glow brighter
B) Resistance of $Y$ will be greater than $X$
C) Heat produced in $Y$ will be greater than $X$
D) Voltage drop in $X$ will be greater than $Y$
Explanation
(a) Resistance of bulb $R = \frac{V^{2}}{P}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ R \propto \frac{1}{P}$
Here $P_{X} = 40\ W,\ and\ P_{Y} = 60\ W$
$\therefore\ \ \ \ \ \ \ R_{X} > R_{Y}$
So, potential drop across bulb $X\ ie,$ of 40 W bulb will be greater and it will glow brighter.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.