Free Electromagnetism MCQs with Answers
1,176 Electromagnetism MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Magnetic flux density and magnetic flux describe the strength of a magnetic field and the field passing through a surface. A charged particle moving through a magnetic field experiences a force perpendicular to its velocity and may follow circular or helical motion, depending on the angle between velocity and field.
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Read the Electromagnetism notesFree MDCAT chapter notes with key terms1,176 questions · page 29 of 59
- A. Faraday's Law
- B. Lenz's Law
- C. Ohm's Law
- D. Kirchoff's Law
Explanation: OPTION A:Faraday's law states that whenever a magnetic flux linking a coil is changed,induced emf is produced in the coil.The magnitude of…
Correct answer: Lenz's Law- A. 22.7 cm
- B. 21.3 cm
- C. 20 cm
- D. 21.9 cm
Explanation: v=5.20 × 106 m/sB=1.30×10-4 Te/m=1.76×1011 C/kgr=?evB=mv2/rBy rearranging:r=(v/B)÷(e/m)r=5.20×106m/s /1.30×10-4 T ÷ 1.76×1011 C/kgr=22.7…
Correct answer: 22.7 cm- A. B =zero
- B. B ⊥ E
- C. Both Options A and B are correct
- D. None of these options is correct
Explanation: Given that, Fe = Fm, which means the electric force is equal to magnetic force, Then Fe = -Fm. qE = -q( v x B), where E = v x B.
Correct answer: B ⊥ E- A. Directly proportional
- B. Inversely proportional
- C. Directly squared proportional
- D. Not enough information is available
Explanation: Using the relation Np/Ns = Is/Ip and by taking the primary current and winding as constant, the secondary current is inversely…
Correct answer: Inversely proportional- A. Electric field
- B. Magnetic field
- C. Both of these options are correct
- D. None of these options are correct
Explanation: Oersted's Law states that when a steady electric current is passed through a metallic conductor, it creates a magnetic field around it.
Correct answer: Magnetic field- A. f∝N
- B. f∝1/N
- C. f∝1(N)2
- D. f∝N2
Explanation: Magnetic flux is denoted by ΦB The magnetic flux value depends on the magnetic field direction and it is a vector quantity.The magnetic…
Correct answer: f∝N- A. 256.33 V
- B. 89.12 V
- C. 0.314 V
- D. 3.1455 V
Explanation: N=100A=0.1ω= ½ revolutions per second or ω= π radians/second [ as 1 revolution/sec=2πradians/sec]B= 0.01 TAS, Emf E = NωAB sin θ E=…
Correct answer: 0.314 V- A. Attractive
- B. Repulsive
- C. Retracting
- D. Opposing
Explanation: If the currents in both wires flow in the same direction, the forces acting on the two wires are attractive and they will move towards…
Correct answer: Attractive- A. Electric field
- B. Magnetic field
- C. Number of turns
- D. None of these options is correct
Explanation: A transformer that increases the voltage from primary to secondary (more secondary winding turns than primary winding turns) is called a…
Correct answer: Number of turns- A. LI
- B. LI2
- C. L2I
- D. (LI)2
Explanation: Self-inductance is the tendency of a coil to resist changes in current in itself.
Correct answer: LI- A. Vs/Vp
- B. IpIs
- C. NsNp
- D. All of these
Explanation: The transformation ratio is defined as the ratio of output voltage to the input voltage of the transformer.
Correct answer: Vs/Vp- A. 0.1 m
- B. 1 m
- C. 10 m
- D. none of them
Explanation: The radius of proton in the circular path is given by , r= mv/ qB Where , V = 10^7 q= 10^11B = 10^-4 Therefore the equation becomes , r =…
Correct answer: 1 m- A. The deflection produced per unit microampere current
- B. The deflection per force
- C. Force per unit area
- D. None of them
Explanation: The correct answer is Option A: The sensitivity of a galvanometer is defined as the deflection produced per unit microampere of current.
Correct answer: The deflection produced per unit microampere current- A. 10
- B. 10 000
- C. 1000
- D. 100 000
Explanation: Current is given as , I = power / voltage Where power = 100kW ( 1 Kw= 1000 watts ) So power = 100,000 Watts Voltage = 10,000 volts So the…
Correct answer: 10- A. Copper loss
- B. Winding loss
- C. Total loss
- D. Core loss
Explanation: The open-circuit test is done to find the core loss of the transformer.
Correct answer: Core loss- A. 1 N
- B. 1.2 N
- C. 1.4 N
- D. 1.6 N
Explanation: According to the formula: F = ILBsin(θ) Where I = Current = 5 A L = length = 2cm = 2/100 m = 0.02m And B = magnetic field/magnetic flux…
Correct answer: 1.2 N- A. Copper
- B. Aluminium
- C. Iron
- D. Steel
Explanation: In transformers, soft iron cores are used because they reduce energy loss and they possess high magnetic permeability which allows…
Correct answer: Iron- A. it causes less amount of power loss
- B. it reduces the possibility of theft
- C. High voltage waves travel faster
- D. generators produce electrical energy at high voltage
Explanation: Option A is correct since high voltage and low current will result in a very low amount of power loss Option B is incorrect since high…
Correct answer: it causes less amount of power loss- A. IvB
- B. IvB2
- C. Iv2B
- D. None of these options are correct
Explanation: The formula for motional EMF is length x speed x magnetic field flux so the correct answer is A.
Correct answer: IvB- A. 0.125 A
- B. 0.5 A
- C. 125 A
- D. 12.5 A
Explanation: Vp = 240 V, Vs = 12VPout = VsIs30W = 12V × IsIS = 2.5 AVs / Vp = Ip / Is VpIp = VsIs240 Ip = 12 × 2.5Ip = 30/ 240Ip = 0.125 AThis is…
Correct answer: 0.125 A