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 23 of 59
- A. Rays that emerge from the wire
- B. Circles centered on the wire
- C. Lines parallel to the wire
- D. Lines perpendicular to the wire
- E. Noncircular ellipses centered on the wire
Explanation: Whenever we have current flowing through a wire, we have concentric circles of magnetic field lines around the wire making it the central…
Correct answer: Circles centered on the wire- A. Magnetic flux
- B. Electric flux
- C. Magnetic induction
- D. Self inductance
Explanation: The magnetic force acting on a unit positive charge moving perpendicular to the magnetic field with a unit vleocity is called magnetic…
Correct answer: Magnetic induction- A. Yes
- B. No
- C. In some cases it is possible
- D. None of these
Explanation: Magnetism is a property that is caused due to separation of poles at atomic level.
Correct answer: No- A. 1840 keV
- B. 1/1840 keV
- C. 1keV
- D. 920 keV
Explanation: Kinetic Energy= eVEnergy depends upon charge not mass so same for proton and electronK.E. = eV = 1 KVe = 1 keV
Correct answer: 1keV- A. e/m2(VB2r2)
- B. e/m=(V/Br)2
- C. e/m=V.r/B
- D. e/m=2V/B2r2
Explanation: The E/m (charge-to-mass ratio) of an electron is given by the formula:em=2V/B2r2 where:e = charge of electronm = mass of electronV =…
Correct answer: e/m=2V/B2r2- A. 0.23 x 10^-1T
- B. 1.67 x 10^-4T
- C. 2.99 x 10^-6T
- D. 3.63 x 10^-8T
- E. 999 x 10^-7T
Explanation: The correct answer is 1.67x10-4T. To find the magnetic flux density (B) at a distance (r) from a long straight wire carrying current (I)…
Correct answer: 1.67 x 10^-4T- A. 6 x 10^-5 m/s
- B. 4.5 x 10^-5 m/s
- C. 3.3 x 10^-6 m/s
- D. 4 x 10^-5 m/s
Explanation: To find the velocity at which the magnetic force equals the weight of the H+ ion, use the formula for magnetic force: Fmagnetic = evB, and…
Correct answer: 4 x 10^-5 m/s- A. -2.0 volts
- B. -3.0 volts
- C. +2.0 volts
- D. +2.5 volts
- E. +3.0 volts
Explanation: Emf = - N (dФ/dt)where number of turns are denoted by N, dФ is the change in flux and dt is the time interval.Change in flux = Final Flux…
Correct answer: +2.0 volts449. _ is a device which makes use of mutual induction for stepping up or down an alternating e.m.f.
- A. Sonometer
- B. Transformer
- C. Ammeter
- D. Voltmeter
- E. Potentiometer
Explanation: Attached below is the answer to the question above:
Correct answer: Transformer- A. 4 Henrys
- B. 5 Henrys
- C. 6 Henrys
- D. 7 Henrys
- E. 8 Henrys
Explanation: Attached below is the solution of question above:
Correct answer: 4 Henrys- A. 4 henrys
- B. 8 henrys
- C. 12 henrys
- D. 16 henrys
- E. 20 henrys
Explanation: Initial currect= I1 = 5.0 A Final current= I2= 0 A change in current , dI= I1 -I2 =5A Time taken for the change= 0.1s Avg emf= 200V e=L…
Correct answer: 4 henrys- A. 7780 ohms
- B. 9980 ohms
- C. 5580 ohms
- D. 4480 ohms
- E. 3380 ohms
Explanation: As we know when converting a galvanometer into a voltmeter, we use the formula Rh=V/Ig -Rg where Rh is the series resistance V is the…
Correct answer: 9980 ohms- A. Self-Inductance
- B. Zero
- C. Mutual-Inductance
- D. Back EMF
Explanation: The emf induced in a circuit is directly proportional to the time rate of change of the magnetic flux through the circuit.
Correct answer: Zero- A. BIL
- B. B²LI
- C. BLI²
- D. Zero
- E. Infinity
Explanation: The formula for the force experienced by a current-carrying conductor is BILsin(θ), where theta represents the angle between the current…
Correct answer: BIL- A. 16
- B. 30
- C. 1000
- D. 2000
- E. 10000
Explanation: Turns(primary)/V(primary)=Turns(secondary)/V(secondary)400 turns / 120 V = X turns / 3000 VX = 3000 * 400 / 120 = 10,000 turns
Correct answer: 10000- A. Decreasing current
- B. Decreasing resistance
- C. Increasing resistance
- D. Increasing voltage
Explanation: Efficient power transmission is achieved by using transformers to increase the voltage, which reduces the current according to the formula…
Correct answer: Increasing voltage- A. 0
- B. 90
- C. 180
- D. Both A and C
Explanation: Magnetic flux is calculated as the product of the magnetic field strength (B) and the area (ΔA) through which it passes, adjusted by the…
Correct answer: Both A and C- A. Current
- B. Voltage
- C. Energy
- D. Power
Explanation: A transformer is use to step up and step down the voltage.The power in the transformer remains constant.
Correct answer: Voltage- A. Maximum current
- B. Minimum current
- C. No current
- D. Intermediate value of current
Explanation: The galvanometer will show no current when a stationary bar magnet is placed near a coil so that the maximum lines of magnetic force pass…
Correct answer: No current460. By changing the current through the same coil, an emf is induced in it, the process is known as:
- A. Rectification
- B. Mutual induction
- C. Self induction
- D. Simple induction
Explanation: Self-induction is the correct answer because it involves the generation of an electromotive force (emf) within the same coil when there is…
Correct answer: Self induction