JEE Main 202228 JuneEvening Shift
- Exam
- JEE Main
- Year
- 2022
- Date
- 28 June
- Shift
- Evening Shift
- Subject
- Physics
- Chapter
- Electromagnetic Induction
JEE Main 2022 · 28 June · Evening Shift · Physics · Electromagnetic Induction
A coil is placed in a time varying magnetic field. If the number of...
A coil is placed in a time varying magnetic field. If the number of turns in the coil were to be halved and the radius of wire doubled, the electrical power dissipated due to the current induced in the coil would be (Assume the coil to be short circuited.)
Options
- ADoubled
- BThe same
- CQuadrupled
- DHalved
Correct answer
B. The same
Step-by-step solution
(\mathrm{P}=\frac{\varepsilon^2}{R})
where, (\varepsilon=) inducedemf (=-\frac{d \phi}{d t})
(\phi=\mathrm{NBA})
(\varepsilon=\mathrm{NA} \frac{\mathrm{dB}}{\mathrm{dt}})
also, (R \propto \frac{1}{\mathrm{r}^2})
where, (\mathrm{R}=) resistance and (\mathrm{r}=) radius of wire
()
This means if the number of turns were quadrupled and the wire radius halved, the electrical power dissipated would be remains same.