JEE Main 2022 (Online) 28th June Evening Shift | Atoms and Nuclei Question 51 | Physics

JEE Main 2022 (Online) 28th June Evening Shift

MCQ (Single Correct Answer)

-1

Let K₁ and K₂ be the maximum kinetic energies of photo-electrons emitted when two monochromatic beams of wavelength $$\lambda$$₁ and $$\lambda$$₂, respectively are incident on a metallic surface. If $$\lambda$$₁ = 3$$\lambda$$₂ then :

$${K_1} > {{{K_2}} \over 3}$$

$${K_1} < {{{K_2}} \over 3}$$

$${K_1} = {{{K_2}} \over 3}$$

$${K_2} = {{{K_1}} \over 3}$$

JEE Main 2022 (Online) 28th June Evening Shift

MCQ (Single Correct Answer)

-1

Following statements related to radioactivity are given below :

(A) Radioactivity is a random and spontaneous process and is dependent on physical and chemical conditions.

(B) The number of un-decayed nuclei in the radioactive sample decays exponentially with time.

(C) Slope of the graph of log_e (no. of undecayed nuclei) Vs. time represents the reciprocal of mean life time ($$\tau$$).

(D) Product of decay constant ($$\lambda$$) and half-life time (T_1/2) is not constant.

Choose the most appropriate answer from the options given below :

(A) and (B) only

(B) and (D) only

(B) and (C) only

JEE Main 2022 (Online) 28th June Morning Shift

MCQ (Single Correct Answer)

-1

The de Broglie wavelengths for an electron and a photon are $$\lambda$$_e and $$\lambda$$_p respectively. For the same kinetic energy of electron and photon, which of the following presents the correct relation between the de Broglie wavelengths of two ?

$${\lambda _p} \propto \lambda _e^2$$

$${\lambda _p} \propto {\lambda _e}$$

$${\lambda _p} \propto \sqrt {{\lambda _e}} $$

$${\lambda _p} \propto \sqrt {{1 \over {{\lambda _e}}}} $$

JEE Main 2022 (Online) 27th June Morning Shift

MCQ (Single Correct Answer)

-1

Match List-I with List-II :

	List - I		List - II
(a)	Ultraviolet rays	(i)	Study crystal structure
(b)	Microwaves	(ii)	Greenhouse effect
(c)	Infrared rays	(iii)	Sterilizing surgical instrument
(d)	X-rays	(iv)	Radar system