1
JEE Main 2024 (Online) 27th January Evening Shift
MCQ (Single Correct Answer)
+4
-1

The threshold frequency of a metal with work function $$6.63 \mathrm{~eV}$$ is :

A
$$16 \times 10^{15} \mathrm{~Hz}$$
B
$$16 \times 10^{12} \mathrm{~Hz}$$
C
$$1.6 \times 10^{15} \mathrm{~Hz}$$
D
$$1.6 \times 10^{12} \mathrm{~Hz}$$
2
JEE Main 2023 (Online) 15th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
The de Broglie wavelength of an electron having kinetic energy $\mathrm{E}$ is $\lambda$. If the kinetic energy of electron becomes $\frac{E}{4}$, then its de-Broglie wavelength will be :
A
$\sqrt{2} \lambda$
B
$2 \lambda$
C
$\frac{\lambda}{2}$
D
$\frac{\lambda}{\sqrt{2}}$
3
JEE Main 2023 (Online) 13th April Evening Shift
MCQ (Single Correct Answer)
+4
-1

Given below are two statements:

Statement I : Out of microwaves, infrared rays and ultraviolet rays, ultraviolet rays are the most effective for the emission of electrons from a metallic surface.

Statement II : Above the threshold frequency, the maximum kinetic energy of photoelectrons is inversely proportional to the frequency of the incident light.

In the light of above statements, choose the correct answer form the options given below

A
Both Statement I and Statement II are true
B
Statement I is true but statement II is false
C
Statement I is false but statement II is true
D
Both Statement I and Statement II are false
4
JEE Main 2023 (Online) 13th April Morning Shift
MCQ (Single Correct Answer)
+4
-1

The difference between threshold wavelengths for two metal surfaces $$\mathrm{A}$$ and $$\mathrm{B}$$ having work function $$\phi_{A}=9 ~\mathrm{eV}$$ and $$\phi_{B}=4 \cdot 5 ~\mathrm{eV}$$ in $$\mathrm{nm}$$ is:

$$\{$$ Given, hc $$=1242 ~\mathrm{eV} \mathrm{nm}\}$$

A
264
B
138
C
540
D
276
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