Doubtly
@Doubtly · Joined Feb 2021
- Answers
- 3,792
- Questions
- 4,963
- Upvotes received
- 428
- What is an ideal solenoid? A solenoid is a long wire wound in the form of a helix. An ideal solenoid is tightly wound and infinitely long, i.e., its turns are closely... 1
- Choosing different Amperean loops, show that out-side an ideal toroid B = 0. From below figure, the inner Amperean loop does not enclose any current while the outer Amperean loop encloses equal number of I_in and I_ou... 1
- What is an ideal toroid? A toroid is a toroidal solenoid. An ideal toroid consists of a long conducting wire wound tightly around a torus, a doughnut-shaped ring, ma... 1
- Explain Magnetic Dipole Moment A current-carrying coil reacts to an external magnetic field in the same way a magnetic dipole does (or a bar magnet). Like a magnetic dipol... 1
- Advantage of radial magnetic field in a moving-coil galvanometer As the coil rotates, its plane is always parallel to the field. That way, the deflecting torque is always a maximum depending only on the cur... 1
- What will happen if the magnetic field in a moving-coil galvanometer is not radial? Suppose the magnetic field is uniform but not radial. Then, when the coil comes to rest after rotation through an angle θ, NIAB cos θ = Kθ (i... 1
- State under what conditions will a charged particle moving through a uniform magnetic field travel in (i) A charged particle travels undeviated through a magnetic field B if its velocity v is parallel or antiparallel to . In this case, the mag... 1
- Explain why the magnetic force on a charged particle cannot change the linear speed and the kinetic energy The magnetic force on a particle carrying a charge q and moving with a velocity v in a magnetic field of induction B is F_m = q v×B . At ever... 1
- Expression for the Lorentz force on a charge due to an electric field as well as a magnetic field A charge q moving with a velocity through a magnetic field of induction B experiences a magnetic force perpendicular both to B and . v Experi... 1
- When current is passed through the conductor, the compass needle deflects. Why? The compass needle is now subjected to the earth’s magnetic field and the magnetic field of the straight conductor. 1
- The wires which connect the battery of an automobile to its starting motor carry a current of 300 A (for a short time). I = 300 A, l = 70 cm, r = 1.5 cm F = fracμ₀ I₁ I₂2 π r = frac4 π × 10⁻⁵ × 300 × 3002 × 1.5 × 10⁻² = 1.2 N The force is repulsive. 1
- An electron travelling west to east enters a chamber having a uniform electrostatic field The force on the electron due to the electric field is south to north. To oppose this the force due to the magnetic field should be to the s... 1
- A charged particle enters an environment of a strong and non-uniform magnetic field varying from point A space-fixed magnetic field cannot do work on moving charge and hence the speed remains the same (so also KE). 1
- A magnetic field that varies in magnitude from point to point but has a constant direction (east to west) The force on a charged particle moving in a magnetic field is F = q( v x B ) = qvB sin θ. If θ = 0° or 180°, force is zero and the particle... 1
- In Exercise. 11 obtain the frequency of revolution of the electron in its circular orbit Frequency in Exercise 11, υ = qB / 2πm = frac1.6 × 10⁻¹⁹ × 6.5 × 10⁻⁴2 × π × 9.1 × 10⁻³¹ = 18 MHz 2
- In a chamber, a uniform magnetic field of 6.5G (1G = 10-4 T) is maintained. B = 6.5 x 10⁻⁴ T, v = 4.8 x 10⁶ms⁻¹ Bqv = fracmv²r r = mv / qB = frac9.1 × 10⁻³¹ × 4.8 × 10⁶1.6 × 10⁻¹⁹ × 6.5 × 10⁻⁴ = 4.2 x 10⁻²m = 4.2 cm 2
- A square coil of side 10 cm consists of 20 turns and carries a current of 12 A. The coil is suspended I = 12A n = 20 B = 0.80 T θ =30° A = 10 x 10= 100cm² = 100 x 10⁴m² τ = n BIA sin θ = 2d x 0.80 x l00 x l0^(-4 )x l2 x sin30° = 0.96 Nm. 1
- A closely wound solenoid 80 cm long has 5 layers of windings of 400 turns each. The diameter of the solenoid is 1.8 cm. l = 80 cm = 80 x 10⁻² m p = 5 N = 400 n = N / l = frac40080 × 10⁻² = 500 For one turn, B = μ₀nl B = 4π x 10⁻⁷ x 500 x 8 For p turns = pB = 5... 1