Φ = (nlBA) Substituting the value of B from (i) Φ = nl (µ0nI ) A = µ0n2AlI Self-inductance of air solenoid L = Φ/I = µ0n2Al If N is total number of turns in length l, then n= N/l Self-inductance L = µ0(N/l)2Al = µ0N2A/l Q. 1. What do you mean by mutual inductance of two nearby coils? Find an expression for mutual inductance of two co-axial solenoid. (5) [CBSE (F) 2013, 2010] Ans. When current flowing in one of two nearby coils is changed, the magnetic flux linked with the other coil changes; due to which an emf is induced in it (other coil). This phenomenon of electromagnetic induction is called the mutual induction. The coil, in which current is changed is called primary coil and the coil in which emf is induced is called the secondary coil. The si unit of mutual inductance is henry. Mutual Inductance: Suppose there are two coils C1 and C2. The current I1 flowing in primary coil c1 ; due to which an effective magnetic flux Φ2 is linked with secondary coil C2 . Φ2=M21I1 , M21 is the mutual inductance of coil 2 w.r.t. coil 1
Φ = (nlBA) Substituting the value of B from (i) Φ = nl (µ0nI ) A = µ0n2AlI Self-inductance of air solenoid L = Φ/I = µ0n2Al If N is total number of turns in length l, then n= N/l Self-inductance L = µ0(N/l)2Al = µ0N2A/l Q. 1. What do you mean by mutual inductance of two nearby coils? Find an expression for mutual inductance of two co-axial solenoid. (5) [CBSE (F) 2013, 2010] Ans. When current flowing in one of two nearby coils is changed, the magnetic flux linked with the other coil changes; due to which an emf is induced in it (other coil). This phenomenon of electromagnetic induction is called the mutual induction. The coil, in which current is changed is called primary coil and the coil in which emf is induced is called the secondary coil. The si unit of mutual inductance is henry. Mutual Inductance: Suppose there are two coils C1 and C2. The current I1 flowing in primary coil c1 ; due to which an effective magnetic flux Φ2 is linked with secondary coil C2 . Φ2=M21I1 , M21 is the mutual inductance of coil 2 w.r.t. coil 1
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