Nuclear density is given by, ρ=34π(R0)3m, where m is mass of proton. Clearly it is independent of A and same for all nucleus.
Radius of the nucleus is given by, R=R0A31.
JEE Main 2023 — Physics Modern Physics
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R
Assertion A : The nuclear density of nuclides B510,L36i,F2656e,N1020eandB83209i can be arranged as ρBiN>ρFeN>ρNeN>ρBN>ρLiN
Reason R : The radius R of nucleus is related to its mass number A as R=R0A31, where R0 is a constant.
In the light of the above statement, choose the correct answer from the options given below :
Held on 30 Jan 2023 · Verified 6 Jul 2026.
Both A and R are true and R is the correct explanation of A
A is false but R is true
A is true but R is false
Both A and R are true but R is NOT the correct explanation of A
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Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The electromagnetic wave exerts pressure on the surface on which they are allowed to fall. Reason (R): There is no mass associated with the electromagnetic waves. In the light of the above statements, choose the correct answer from the options given below :
The following diagram shows a Zener diode as a voltage regulator. The Zener diode is rated at $V_{z}=5 \mathrm{~V}$ and the desired current in load is 5 mA. The unregulated voltage source can supply upto 25 V. Considering the Zener diode can withstand four times of the load current, the value of resistor $R_{S}$ (shown in circuit) should be $\_\_\_\_$ $\Omega$. 
The minimum frequency of photon required to break a particle of mass 15.348 amu into $4 \alpha$ particles is $\_\_\_\_$ kHz. [mass of He nucleus = $4.002 \mathrm{amu}, 1 \mathrm{amu}=1.66 \times 10^{-27} \mathrm{~kg}, \mathrm{~h}=6.6 \times 10^{-34} \mathrm{~J}. \mathrm{s}$ and $\mathrm{c}=3 \times 10^{8} \mathrm{~m} / \mathrm{s}$ ]
The work function of a metal is 4.2 eV. The threshold wavelength for photoelectric emission is approximately:
A voltage regulating circuit consisting of Zener diode, having break-down voltage of 10 V and maximum power dissipation of 0.4 W, is operated at 15 V. The approximate value of protective resistance in this circuit is $\_\_\_\_$ $\Omega$.
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