Question

In which of the following situations the heavier of the two particles has smaller de Broglie wavelength? The two particles

• A. move with the same speed
• B. move with the same linear momentum
• C. move with the same kinetic energy
• D. have fallen through the same height

Answer 1

Answer: (A), (C), (D)

The correct options are
A move with the same speed
C move with the same kinetic energy
D have fallen through the same height

$\lambda =\frac{h}{mv}$

If $h$ = same and if $m1>m2$,

then $\lambda 1<\lambda 2$ Hence $D$ option is correct

Similarly If $v$ = same and $m1>m2$

then also $\lambda 1<\lambda 2$ Hence option $A$ is correct

Also,

$\lambda =\frac{h}{\sqrt{2mKE}}$

hence If $KE$ is same and $m1>m2$,

then also $\lambda 1<\lambda 2$ , Hence option $c$ is also correct.