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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- A. Distance
- B. Current on them
- C. Charge on them
- D. None of these options are correct
Explanation: Magnetic force between two wires is inversely proportional to distance because it is given by:μ0 I1I2 / 2πrHence, Option A is correct.
Correct answer: Distance- A. Zero
- B. 1 Newton
- C. 10-4 Newton
- D. 1 dyne
Explanation: The formula of Magnetic force is F=BIL sinθF=1x 1 x 1 x 0 = 0 Since the wire is placed parallel to the magnetic field, No force acts on…
Correct answer: Zero- A. BA=3BB
- B. BA=(BB)/3
- C. BA=BB
- D. BA=4BB
Explanation: The magnetic field in the solenoid is independent of length and cross-section area;B= 𝛍 nIn=I/Ln= number of turnsI=currentL=lengthB…
Correct answer: BA=BB- A. Its length
- B. Its length and current in it
- C. Its length and number of turns in it
- D. Its length, number of turns and current in it
Explanation: Inside a solenoid, B=μ0IN/Lwhere I is the current,N is the no. of turns L is length Therefore, magnetic field inside a solenoid depends on…
Correct answer: Its length, number of turns and current in it- A. Mechanical to electrical
- B. Electrical to mechanical
- C. Electrical to heat
- D. Heat to electrical
Explanation: AC generators convert mechanical energy to electrical and AC motors convert electrical energy to mechanical.
Correct answer: Mechanical to electrical- A. 3.15 x 10 ̄² m
- B. 4.25 x 10 ̄² m
- C. 9.48 x 10 ̄² m
- D. 17.77 x 10 -2 m
- E. 19.91 x 10 ̄² m
Explanation: The formula for the radius isr = mv/qB= (9.11 x 10-31) (2 x 102) / (1.6 x 10-19) (1.2 x 10-3)=9.48 x 10-7mHence the correct option is C.
Correct answer: 9.48 x 10 ̄² m- A. Low; high
- B. High; low
- C. Low; low
- D. High; high
Explanation: The correct option is B (High frequency...low frequency) because fluorescence involves the absorption of energy of high frequency (short…
Correct answer: High; low- A. Diffraction
- B. Interference
- C. Polarization
- D. Optical Rotation
Explanation: Diffraction is the process of light bending around an obstacle or spreading out after it moves through a small space.
Correct answer: Diffraction- A. Diffraction
- B. Interference
- C. Polarization
- D. Optical Rotation
Explanation: Diffraction is the process of light bending around an obstacle or spreading out after it moves through a small space.
Correct answer: Diffraction- A. Zero
- B. Equal to the force on the proton
- C. Less than the force on the proton
- D. Greater than the force on the proton
Explanation: When a charged particle, such as a proton, moves through a magnetic field, it experiences a force known as the magnetic Lorentz force.
Correct answer: Equal to the force on the proton- A. If an electron's movement is parallel to the magnetic field. it will rotate
- B. If the electron's movement is parallel to the magnetic field, it will rotate anticlockwise
- C. If an electron enters perpendicular to the field force it would be parallel to the plane
- D. If an electron enters perpendicular to the field force will be maximum
Explanation: If an electron enters perpendicular to the field, the force will be maximum, because according to theformula of force on a moving…
Correct answer: If an electron enters perpendicular to the field force will be maximum- A. Towards the outside
- B. Towards the inside
- C. Parallel to its motion
- D. No force acts on it
Explanation: The electron is moving along the axis with velocity VForce = q(V x B)Velocity and magnetic field are in the same direction or at an angle…
Correct answer: No force acts on it- A. 1840 keV
- B. 1/1840 keV
- C. 1 keV
- 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: 1 keV- A. 6 x 10^-5 m/s
- B. 3.5 x 10^-5 m/s
- C. 3.3 x 10^-6 m/s
- D. 4 x 10^-5 m/s
Explanation: According to given conditionForce = WeightevB = mgv = mg/eBPutting the values, we obtain
Correct answer: 4 x 10^-5 m/s- A. qBr
- B. qB/r
- C. q/(Br)
- D. B
Explanation: Here the centripetal force will balance the magnetic force. So, mv2/r=qvB or mv=qBr Thus, linear momentum, p=mv=qBr
Correct answer: qBr- A. magnitude of charge
- B. Speed of the moving charge (v)
- C. Magnetic field of induction (B)
- D. All of these
- E. None of these
Explanation: Force on the charge in the magnetic field depends on the magnitude of the charge, the velocity of the charge, and the magnetic field of…
Correct answer: All of these- A. 0 degree
- B. 90 degrees
- C. 180 degrees
- D. 45 degrees
Explanation: Magnetic flux is the product of the magnetic induction and vector area elementFlux= B.ΔAFlux=BΔAcosθThe maximum value(=1) of cosθ occurs…
Correct answer: 0 degree- A. Maximum current
- B. Minimum current
- C. No current
- D. Intermediate value of current
Explanation: When the magnet is stationary and its magnetic field is not changing, there will be no induced electromotive force (EMF) and therefore no…
Correct answer: No current- A. Straight
- B. Circular
- C. Curve
- D. Helical
Explanation: If a charged particle enters at an angle, then its motion is a combination of certucal and horizontal component of velocity.
Correct answer: Helical- A. Normal to the solenoid
- B. The axis of the solenoid
- C. Can't be taken
- D. None of the above
Explanation: Option A: The magnetic field inside a solenoid is parallel to the axis of the solenoid, so the magnetic field is not normal to the…
Correct answer: The axis of the solenoid