1
COMEDK 2024 Evening Shift
+1
-0

A particle of mass $$2 \mathrm{mg}$$ has the same wavelength as a neutron moving with a velocity of $$3 \times 10^5 \mathrm{~ms}^{-1}$$. The velocity of the particle is (mass of neutron is $$1.67 \times 10^{-27} \mathrm{Kg}$$)

A
$$2.5 \times 10^{-16} \mathrm{~ms}^{-1}$$
B
$$1.5 \times 10^{-13} \mathrm{~ms}^{-1}$$
C
$$2.5 \times 10^{-13} \mathrm{~ms}^{-1}$$
D
$$1.5 \times 10^{-16} \mathrm{~ms}^{-1}$$
2
COMEDK 2024 Morning Shift
+1
-0

The threshold frequency for a metal surface is '$$n_0$$'. A photo electric current '$$I$$' is produced when it is exposed to a light of frequency $$\left(\frac{11}{6}\right) \mathrm{n}_{\mathrm{o}}$$ and intensity $$\mathrm{I}_{\mathrm{n}}$$. If both the frequency and intensity are halved, the new photoelectric current '$$\mathrm{I}^1$$' will become:

A
$$\mathrm{I}^1=\frac{1}{4} \mathrm{I}$$
B
$$\mathrm{I}^1=2 \mathrm{I}$$
C
$$\mathrm{I^1=0}$$
D
$$\mathrm{I}^1=\frac{1}{2} \mathrm{I}$$
3
COMEDK 2024 Morning Shift
+1
-0

The mass of a particle $$\mathrm{A}$$ is double that of the particle $$\mathrm{B}$$ and the kinetic energy of $$\mathrm{B}$$ is $$\frac{1}{8}$$th that of A then the ratio of the de- Broglie wavelength of A to that of B is:

A
1 : 2
B
2 : 1
C
1 : 4
D
4 : 1
4
COMEDK 2024 Morning Shift
+1
-0

The difference in energy levels of an electron at two excited levels is $$13.75 \mathrm{~eV}$$. If it makes a transition from the higher energy level to the lower energy level then what will be the wave length of the emitted radiation? [given $$h=6.6 \times 10^{-34} \mathrm{~m}^2 \mathrm{~kg} \mathrm{~s}^{-1} ; c=3 \times 10^8 \mathrm{~ms}^{-1} ; 1 \mathrm{~eV}=1.6 \times 10^{-19} \mathrm{~J}$$]

A
$$900 \mathrm{~nm}$$
B
$$9^0 \mathrm{~A}$$
C
$$9000 \mathrm{~nm}$$
D
$$900^{\circ} \mathrm{A}$$
EXAM MAP
Medical
NEET