Start learning →

ISC Class 12 Moving Charges and Magnetism — practice questions — page 3

Explore 133 free Moving Charges and Magnetism questions in ISC Class 12 Physics. Open each question or exercise to read its content, reference answers and available explanation.

Practise Moving Charges and Magnetism with Quill →

Moving Charges and Magnetism questions and exercises with answers

Showing questions 61–90 of 133.

An electron enters a uniform magnetic field B at angle θ to B with speed v. The pitch of its helical path isRead the answer and worked solution →A cyclotron of dee radius R accelerates ions of charge q, mass m in a magnetic field B. The maximum kinetic energy isRead the answer and worked solution →A circular loop of radius R carries current I. The magnetic field at a point on its axis at distance x from the centre isRead the answer and worked solution →At the very end of a long solenoid, the magnetic field along the axis isRead the answer and worked solution →A magnetic dipole with moment m makes angle θ with a uniform field B. The torque on the dipole has magnitudeRead the answer and worked solution →An electron moves east in a magnetic field directed north. The magnetic force on the electron pointsRead the answer and worked solution →A cyclotron operates at frequency f in a magnetic field B. The charge-to-mass ratio of the accelerated ion isRead the answer and worked solution →Cyclotrons are not used to accelerate electrons becauseRead the answer and worked solution →A charge q moves with velocity v through a region with electric field E and magnetic field B. The net electromagnetic force on it isRead the answer and worked solution →Reading the Lorentz forceRead the answer and worked solution →Force on a current wireRead the answer and worked solution →The current carrying conductorRead the answer and worked solution →The cyclotron machineRead the answer and worked solution →Formula to what it describesRead the answer and worked solution →Using Biot-SavartRead the answer and worked solution →Odd one out: magnetismRead the answer and worked solution →Which is largerRead the answer and worked solution →Odd one out: what a current doesRead the answer and worked solution →Zero work, changing directionRead the answer and worked solution →Moving charges, mixed checkRead the answer and worked solution →A circular coil of N turns and radius R carries current I. Its magnetic dipole moment isRead the answer and worked solution →The Lorentz forceRead the answer and worked solution →A long solenoid has 1000 turns per metre and carries 2 A. The magnetic field strength inside isRead the answer and worked solution →A square coil of side 0.1 m, with 50 turns, carries 1 A in a 0.2 T field. The maximum torque on the coil isRead the answer and worked solution →Charge in a uniform fieldRead the answer and worked solution →Count and computeRead the answer and worked solution →Field of a circular coilRead the answer and worked solution →NEET · Physics · Right-Hand RulesRead the answer and worked solution →Two long parallel wires 0.1 m apart carry 5 A and 10 A in the same direction. The force per unit length on each wire isRead the answer and worked solution →The self-inductance of a long air-cored solenoid of length $\ell$, cross-sectional area $A$ and total number of turns $N$ is:Read the answer and worked solution →

Worked practice questions

An electron enters a uniform magnetic field B at angle θ to B with speed v. The pitch of its helical path is

  1. 2πm v sin θ / (eB)
  2. 2πm v cos θ / (eB)
  3. 2πm v / (eB)
  4. m v cos θ / (eB)
Show answer and solution

Correct answer: B. 2πm v cos θ / (eB)

1. Decompose velocity: parallel v∥ = v cos θ and perpendicular v⊥ = v sin θ. 2. The perpendicular component drives circular motion with period T = 2πm/(eB). 3. The parallel component moves the centre of the circle linearly at v cos θ. 4. Pitch = distance moved along the axis in one period = v cos θ · T = 2πm v cos θ/(eB). _Source: syllabus Physics Ch 4 "Moving Charges and Magnetism", §4.3_

Open this question →

A cyclotron of dee radius R accelerates ions of charge q, mass m in a magnetic field B. The maximum kinetic energy is

  1. qBR
  2. q²B²R²/(2m)
  3. qBR²/(2m)
  4. q²B²/(2mR)
Show answer and solution

Correct answer: B. q²B²R²/(2m)

1. At the edge of the dees, the orbit radius equals R: qvB = mv²/R gives v_max = qBR/m. 2. Kinetic energy K = ½ m v_max². 3. Substitute v_max: K = ½ m (qBR/m)². 4. Simplify: K = q²B²R²/(2m). This is the maximum extracted KE. _Source: syllabus Physics Ch 4 "Moving Charges and Magnetism", §4.4.2_

Open this question →

A circular loop of radius R carries current I. The magnetic field at a point on its axis at distance x from the centre is

  1. μ₀IR² / 2(R²+x²)^(3/2)
  2. μ₀I(R²+x²)^(1/2) / 2R²
  3. μ₀IR / 2(R²+x²)
  4. μ₀I / 2R
Show answer and solution

Correct answer: A. μ₀IR² / 2(R²+x²)^(3/2)

1. Apply Biot-Savart to each current element on the loop; vertical components cancel by symmetry. 2. Each element contributes dB·sin α along the axis, where sin α = R/(R²+x²)^(1/2). 3. Integrating around the loop gives B = μ₀IR² / (2(R²+x²)^(3/2)). 4. At x = 0 the formula reduces to μ₀I/(2R), as expected for the centre. _Source: syllabus Physics Ch 4 "Moving Charges and Magnetism", §4.6_

Open this question →

How to practise

  1. Choose a Moving Charges and Magnetism question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

Put it into practice

Continue with Moving Charges and Magnetism practice for ISC Class 12. Read explanations as you go. No signup form needed to start.

Practise Moving Charges and Magnetism →

More Physics topics

Current ElectricityElectromagnetic Induction & Alternating CurrentSemiconductor ElectronicsRay Optics and Optical InstrumentsElectromagnetic WavesAtoms and NucleiDual Nature of Radiation and MatterElectric Charges and Fields