Get NCERT Exemplar Solutions for CBSE Class 12 Physics ‒ Chapter 5: Magnetism and Matter. Here, students will get detailed solutions of very short answer type question i.e., question number 5.11 to question 5.15. Solutions of multiple choice questions with single correct answer (MCQ I) and multiple choice questions with multiple correct answers (MCQ II) are already available. Solutions of short answer type questions and long answer type questions will be available in further parts.
NCERT Exemplar Solutions for CBSE Class 12 Physics, Chapter 5 (from question number 5.11 to 5.15) are given below:
Question 5.11: A proton has spin and magnetic moment just like an electron. Why then its effect is neglected in magnetism of materials?
Question 5.12: A permanent magnet in the shape of a thin cylinder of length 10 cm has M = 106 A/m. Calculate the magnetisation current IM.
Intensity of magnetization = M = 106 A/m.
Length of cylinder = l = 10cm = 10 ´ 10-2 m = 0.1 m
Let, magnetisation current = IM
As, M = IM/l
⇒ IM = M × l = 106 × 0.1 = 105A
Question 5.13: Explain quantitatively the order of magnitude difference between the diamagnetic susceptibility of N2 (~5 × 10–9) (at STP) and Cu (~10–5).
Question 5.14: From molecular view point, discuss the temperature dependence of susceptibility for diamagnetism, paramagnetism and ferromagnetism.
Diamagnetism is due to orbital motion of electrons developing magnetic moments opposite to applied field and hence is not much affected by temperature.
Paramagnetism & ferromagnetism is due to alignments of atomic magnetic moments in the direction of the applied field. As temperature increases, this aligment is disturbed and hence susceptibilities of both decrease as temperature increases.
Question 5.15: A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet.
(i) In which direction will it move?
(ii) What will be the direction of it’s magnetic moment?
The magnetic nature of superconducting material and Nitrogen are diamagnetic in nature.
If a ball of superconducting material is dipped in liquid nitrogen then it behaves as diamagnetic material.
When it is placed near a bar magnet, it will be feebly magnetized opposite to the direction of magnetizing field, therefore, it will
(i) Away from the magnet.
(ii) Magnetic moment is from left to right.
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