Two large parallel plates are connected with the terminal of 100 V power supply. These plates have a fine hole at the centre. An electron having energy 200 V is so directed that it passes through the holes. When it comes out its de-Broglie wavelength is

Question

Two large parallel plates are connected with the terminal of 100 V power supply. These plates have a fine hole at the centre. An electron having energy 200 V is so directed that it passes through the holes. When it comes out its de-Broglie wavelength is (A) 1.22 mathringA (B) 1.75 mathringA (C) 2 mathringA (D) None of these

Tardigrade Admin · Accepted Answer

Energy of the electron, when it comes out from the second plate =200 V -100 V =100 V Hence accelerating potential difference =100 V λ text electron =(12.27/√V) =(12.27/√100)=1.23 mathringA

Q. Two large parallel plates are connected with the terminal of $100 V$ power supply. These plates have a fine hole at the centre. An electron having energy $200 V$ is so directed that it passes through the holes. When it comes out its de-Broglie wavelength is

$1.22 \overset{˚}{A}$

$1.75 \overset{˚}{A}$

$2 \overset{˚}{A}$

None of these

Energy of the electron, when it comes out from the second plate
$= 200 V - 100 V = 100 V$
Hence accelerating potential difference $= 100 V$
$λ_{electron} = \frac{12.27}{V}$
$= \frac{12.27}{100} = 1.23 \overset{˚}{A}$

Q. Two large parallel plates are connected with the terminal of 100V power supply. These plates have a fine hole at the centre. An electron having energy 200V is so directed that it passes through the holes. When it comes out its de-Broglie wavelength is

1.22A˚

1.75A˚

2A˚