Question

If an electron enters into space between the plates of a parallel plate capacitor at an angle $\alpha$ with the plates and leaves at an angle $\beta$ to the plates .The ratio of its kinetic energy while entering the capacitor to that while leaving will be

• A. $\left(\frac{cos\,\alpha}{cos\,\beta}\right)^2$
• B. $\left(\frac{cos\,\beta}{cos\,\alpha}\right)^2$
• C. $\left(\frac{sin\,\alpha}{sin\,\beta}\right)^2$
• D. $\left(\frac{sin\,\beta}{sin\,\alpha}\right)^2$

Answer 1

Answer: (B)

$\left(\frac{cos\,\beta}{cos\,\alpha}\right)^2$

Answer 2

Answer (b) $\left(\frac{cos\,\beta}{cos\,\alpha}\right)^2$