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Solve the following.
An electron emitted by a heated cathode and accelerated through a potential difference of , enters…
An electron emitted by a heated cathode and accelerated through a potential difference of $2\text{ kV}$, enters a region with a uniform magnetic field of $0.15\text{ T}$. Determine the radius and the trajectory of the electron if the field is:
(a) transverse to its initial velocity.
Answer
Answer
Official answer key$K.E. = \frac{1}{2}mv^2 = eV$
$v = \sqrt{\frac{2eV}{m}} = 2.65 \times 10^7$ m/s
$\frac{mv^2}{r} = qvB\sin\theta$
$\therefore r = \frac{mv}{qB} = 9.95 \times 10^{-4}$ m [Circular]
Final answer: $9.95 \times 10^{-4}$ m
From ISC 2025 Practice Physics, question 73(a).
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