JEE PYQ: Magnetic Effects Of Current Question 21
Question 21 - 2020 (06 Sep 2020 Shift 1)
An electron is moving along $+x$ direction with a velocity of $6 \times 10^6$ ms$^{-1}$. It enters a region of uniform electric field of $300$ V/cm pointing along $+y$ direction. The magnitude and direction of the magnetic field set up in this region such that the electron keeps moving along the $x$ direction will be:
(1) $3 \times 10^{-4}$ T, along $+z$ direction
(2) $5 \times 10^{-3}$ T, along $-z$ direction
(3) $5 \times 10^{-3}$ T, along $+z$ direction
(4) $3 \times 10^{-4}$ T, along $-z$ direction
Show Answer
Answer: (3) $5 \times 10^{-3}$ T, along $+z$ direction
Solution
$B = \frac{E}{v} = \frac{3 \times 10^4}{6 \times 10^6} = 5 \times 10^{-3}$ T along $+z$ direction.
BETA
