Magnetism and Electromagnetism | Practice MCQs Physics for Mdcat | mosaicbro.com

Magnetism and Electromagnetism | Practice MCQs Physics for Mdcat

7 of 127 questions (Page 18 of 19)

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120 The phenomenon in which a change of current in one coil produces an induced emf in another coil nearby is called:
Correct Answer: C
Explanation: Mutual induction involves two coupled coils.
121 A force of 5 N is acting on a wire of length 1 m, held perpendicular in a uniform magnetic field of strength 5 web/m² then the value of current passing through it will be:
Correct Answer: C
Explanation: $I = F/(BL) = 5/(5 \times 1) = 1$ A.
122 The particle which cannot be deflected in a magnetic field is:
Correct Answer: D
Explanation: Neutrons are neutral and unaffected by magnetic fields.
123 A particle of charge ‘q’ and mass ‘m’ moving with a velocity ‘v’ enters perpendicularly in a uniform magnetic field ‘B’ describes a circular path. What will be the radius of that path?
Correct Answer: A
Explanation: Radius $r = mv/(qB)$.
124 240 KW electric power is sent to an area 20 km away from the power plant. If the transformer lines have total resistance of 5 Ohm, then $24 \times 10^5$ volts, the power loss will be:
Correct Answer: A
Explanation: Power loss $P_{\text{loss}} = I^2R = (P/V)^2 R = (240000/240000)^2 \times 5 = 200$ W.
125 If a certain transformer having 200 turns in its primary coil converts 11000 voltage to 220 volts for domestic purpose then the number of turns in secondary coil should be:
Correct Answer: B
Explanation: Turns ratio $N_s = N_p \times (V_s/V_p) = 200 \times (220/11000) = 4$.
126 Transformer is used to:
Correct Answer: C
Explanation: Transformers adjust AC voltage up or down.
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