Question:

An electron accelerated through a potential difference \(V_1\) has a de-Broglie wavelength of \(λ\). When the potential is changed to \(V_2\), its de-Broglie wavelength increases to \(2λ\). The value of \((V_1/V_2)\) is equal to

Show Hint

For an electron, \(\lambda\propto\frac{1}{\sqrt V}\).
Updated On: Oct 1, 2026
  • \(3:1\)
  • \(9:4\)
  • \(3:2\)
  • \(4:1\)
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is D

Solution and Explanation

Step 1: Understanding the Concept:
An electron accelerated through \(V\) has \(\lambda = \frac{h}{\sqrt{2meV}}\), so \(\lambda\propto V^{-1/2}\).

Step 2: Compare:
\(\frac{\lambda_2}{\lambda_1} = \sqrt{\frac{V_1}{V_2}} = 2\), so \(\frac{V_1}{V_2} = 4\).

Step 3: Check:
Doubling the wavelength means quartering the voltage, which fits \(V_1:V_2 = 4:1\).

Final Answer:
The ratio \(V_1:V_2\) is \(4:1\), option (D). \[ \boxed{4:1} \]
Was this answer helpful?
0
0