Electromagnetic Induction — Part 1 MCQs with Explanations

Let's break down this problem to understand how to calculate the total inductance of two coils connected in series aiding! First, let's define some key terms: * Inductance (L): A coil's ability to store energy in a magnetic field, measured in Henries (H). In our case, L1 = 8 mH and L2 = 18 mH. * Coefficient of Coupling (k): A number between 0 and 1 that describes how effectively the magnetic field of one coil links with the other. Here, k = 0.5. A value of 1 means perfect coupling. * Mutual Inductance (M): The inductance due to the interaction of the magnetic fields of the two coils. It's how much one coil's current affects the voltage in the other coil. The formula for Mutual Inductance (M) is: M = k * sqrt(L1 * L2) Let's calculate M: M = 0.5 * sqrt(8 mH * 18 mH) = 0.5 * sqrt(144 mH²) = 0.5 * 12 mH = 6 mH When coils are connected in series aiding (also known as series cumulative), their magnetic fields add up. The formula for the total inductance (L_total) in series aiding is: L_total = L1 + L2 + 2M Now, let's plug in the values: L_total = 8 mH + 18 mH + 2 * 6 mH = 8 mH + 18 mH + 12 mH = 38 mH Therefore, the total inductance will be 38 mH . The correct answer is Option B .

Self-inductance is the correct answer to “The property of coil by which a counter e.m.f. is induced in it when the current through the coil changes is known as”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Inductance only is the correct answer to “Which circuit element(s) will oppose the change in circuit current”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Inductance is the correct answer to “Which of the following circuit elements will oppose the change in circuit current”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

1.0 is the correct answer to “In case all the flux from the current in coil 1 links with coil 2, the coefficient of coupling will be”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

600 uH is the correct answer to “Two 300 uH coils in series without mutual coupling have a total inductance of”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Coulomb/volt ampere is the correct answer to “Which of the following is not a unit of inductance”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Henry is the correct answer to “Which of the following is unit of inductance”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Infinite resistance and zero inductance is the correct answer to “An open coil has”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

6 mH is the correct answer to “The self inductances of two coils are 8 mH and 18 mH. If the coefficient of coupling is 0.5, the mutual inductance of the coils is”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Yes is the correct answer to “Reversing the field or the current will reverse the force on the conductor.”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

No is the correct answer to “Increasing the field or increasing the current will decrease the force on the conductor.”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

True is the correct answer to “A moving magnetic field will produce the same effect as a conductor that is moving.”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Air core is the correct answer to “Which of the fpllowing inductor will have the least eddy current losses”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

0.5 s is the correct answer to “A 500 turns solenoid develops an average induced voltage of 60 V. Over what time interval must a flux change of 0.06 Wb occur to produce such a voltage”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

5000 ohms is the correct answer to “A coil with negligible resistance has 50V across it with 10 mA. The inductive reactance is”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Actual power of the circuit is zero is the correct answer to “For a purely inductive circuit which of the following is true”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

3 mH is the correct answer to “The core of a coil has a length of 200 mm. The inductance of coil is 6 mH. If the core length is doubled, all other quantities, remaining the same, the inductance will be”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

48 mH is the correct answer to “A 200 turn coil has an inductance of 12 mH. If the number of turns is increased to 400 turns, all other quantities (area, length etc.) remaining the same, the inductance will be”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

4 A/s is the correct answer to “An e.m.f. of 16 volts is induced in a coil of inductance 4H. The rate of change of current must be”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Inductance is the correct answer to “Which of the following circuit element stores energy in the electromagnetic field”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Air core is the correct answer to “Which of the following inductor will have the least eddy current losses”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

100 N is the correct answer to “Find the force acting on a conductor 3m long carrying a current of 50 amperes at right angles to a magnetic field having a flux density of 0.67 tesla”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Doubled is the correct answer to “Both the number of turns and the core length of an inductive coil are doubled. Its self-inductance will be”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Yes is the correct answer to “The polarity of the induced voltage can be determined by using the left-hand generator rule.”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

25 V is the correct answer to “A conductor 2 meters long moves at right angles to a magnetic field of flux density 1 tesla with a velocity of 12.5 m/s. The induced e.m.f. in the conductor will be”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Produce current opposite to the increasing current is the correct answer to “If current in a conductor increases then according to Lenz's law self-induced voltage will”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

12 H is the correct answer to “Two coils have self-inductances of 10 H and 2 H, the mutual inductance being zero. If the two coils are connected in series, the total inductance will be”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Variation in voltage to the coil is the correct answer to “A coil is wound on iron core which carries current I. The self-induced voltage in the coil is not affected by”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

All of the above is the correct answer to “Mutually inductance between two magnetically coupled coils depends on”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

5 H is the correct answer to “Current changing from 8 A to 12 A in one second induced 20 volts in a coil. The value of inductance is”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

350 mH is the correct answer to “A coil induces 350 mV when the current changes at the rate of 1 A/s. The value of inductance is”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Longer the delay in establishing steady current through it is the correct answer to “Higher the self-inductance of a coil,”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

When more length for the same number of turns is provided is the correct answer to “The inductance of a coil will increase under all the following conditions except”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

No is the correct answer to “The self-inductance of the coil may be defined as equal to the e.m.f. induced in volts when the current in the circuit changes at the rate of unit Weber turns.”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Cuts magnetic flux is the correct answer to “As per Faraday's laws of electromagnetic induction, an e.m.f. is induced in a conductor whenever it”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Mutual inductance and self inductance of two coils is the correct answer to “The coefficient of coupling between two air core coils depends on”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Both A and B is the correct answer to “Air-core coils are practically free from”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

The laminations are insulated from each other is the correct answer to “A laminated iron core has reduced eddy-current losses because”. This question is standard in competitive examination syllabi for Electromagnetic Induction.

Magnetic field is the correct answer to “In case of an inductance, current is proportional to”. This question is standard in competitive examination syllabi for Electromagnetic Induction.