1
JEE Main 2023 (Online) 31st January Morning Shift
+4
-1 If a source of electromagnetic radiation having power $$15 \mathrm{~kW}$$ produces $$10^{16}$$ photons per second, the radiation belongs to a part of spectrum is.

(Take Planck constant $$h=6 \times 10^{-34} \mathrm{Js}$$ )

A
Gamma rays
B
C
Micro waves
D
Ultraviolet rays
2
JEE Main 2023 (Online) 30th January Evening Shift
+4
-1 An electron accelerated through a potential difference $V_{1}$ has a de-Broglie wavelength of $\lambda$. When the potential is changed to $V_{2}$, its de-Broglie wavelength increases by $50 \%$. The value of $\left(\frac{V_{1}}{V_{2}}\right)$ is equal to
A
$\frac{3}{2}$
B
4
C
3
D
$\frac{9}{4}$
3
JEE Main 2023 (Online) 30th January Morning Shift
+4
-1 A small object at rest, absorbs a light pulse of power $$20 \mathrm{~mW}$$ and duration $$300 \mathrm{~ns}$$. Assuming speed of light as $$3 \times 10^{8} \mathrm{~m} / \mathrm{s}$$, the momentum of the object becomes equal to :

A
$$1 \times 10^{-17} \mathrm{~kg} \mathrm{~m} / \mathrm{s}$$
B
$$0.5 \times 10^{-17} \mathrm{~kg} \mathrm{~m} / \mathrm{s}$$
C
$$3 \times 10^{-17} \mathrm{~kg} \mathrm{~m} / \mathrm{s}$$
D
$$2 \times 10^{-17} \mathrm{~kg} \mathrm{~m} / \mathrm{s}$$
4
JEE Main 2023 (Online) 29th January Morning Shift
+4
-1

The threshold wavelength for photoelectric emission from a material is 5500 $$\mathop A\limits^o$$. Photoelectrons will be emitted, when this material is illuminated with monochromatic radiation from a

A. 75 W infra-red lamp

B. 10 W infra-red lamp

C. 75 W ultra-violet lamp

D. 10 W ultra-violet lamp

Choose the correct answer from the options given below :

A
C only
B
A and D only
C
C and D only
D
B and C only
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