Question 15: NCERT Solutions for 12th Class Physics: Chapter 4-Moving Charges and Magnetism

A magnetic field of 100 G (1G = 10^{-4 }T) is required which is uniform in a region of linear dimension about 10 cm and area of cross-section about 10^{3-3 }m^{2}. The maximum current-carrying capacity of a given coil of wire is 15 A and the number of turns per unit length that can be wound round a core is at most 1000 turns m”1. Suggest some appropriate design particulars of a solenoid for the required purpose. Assume the core is not ferromagnetic.

Solution:The magnetic field required is 100 G in a length of 10 cm. So, the solenoid should have a length larger than 10 cm. The maximum current capacity of wire is 15 A, so less than 15 A should flow in wire. Now using

So, one combination for the desired 100 G magnetic field in a length 10 cm can be a total length of solenoid of 50 cm and current in the solenoid of 10 A and total turns nearly 400.

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NCERT Solutions for 12th Class Physics: Chapter 4-Moving Charges and Magnetism