Doubtly
@Doubtly · Joined Feb 2021
- Answers
- 3,792
- Questions
- 4,033
- Upvotes received
- 424
- 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
- Two long and parallel straight wires A and B carrying currents of 8.0 A and 5.0 A I₁ = 8.0 A I₂ = 5.0 A r = 4.0 cm = 4.0 x 10^(-2 )m l = 10 cm = 0.1 m F = frac2 × 10⁻⁷ I₁ I₂ lr = frac2 × 10⁻⁷ × 8 × 5 × 0.14 × 10⁻² = 2 x 10... 1
- A 3.0 cm wire carrying a current of 10 A is placed inside a solenoid perpendicular to its axis I = 3.0 cm = 3.0 x 10⁻² m I = 10 A B = 0.27 T F = BIl = 0.27 x 10 x 3 x 10⁻² = 8.1 x 10⁻² N 1
- What is the magnitude of magnetic force per unit length on a wire carrying a current of 8 A and making an angle I = 8A, B = 0.15 T and θ = 30° F = BI1 sin θ Therefore, force per unit length on the wire, F = 0.15 × 8 x 1 x sin30° = 0.15 x 8 x 1 x 0.5 =... 1
- A horizontal overhead power line carries a current of 90 A in east to west direction. I = 90 A, r = 1.5 m B = fracμ₀ I2 π r = frac4 π × 10⁻⁷ × 902 π × 1.5 = 1.2 x 10⁻⁵ T (South) 1
- A long straight wire in the horizontal plane carries a current of 50 A in north to south direction. Give the magnitude I = 50 A, r = 2.5 m B = fracμ₀ I2 π r = frac4 π × 10⁻⁷ × 502 π × 2.5 = 4 x 10⁻⁶ T upwards. (due to the wire alone) 1
- A long straight wire carries a current of 35 A. What is the magnitude of the field B at a point 20 cm from the w ire? I = 35 A, r = 20 cm = 20 x 10⁻² m B = fracμ₀ I2 π r = frac4 π × 10⁻⁷ × 352 π × 20 × 10⁻² = 3.5 x 10^(-5 )T 1
- A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a current of 0.40 A. n = 100, I = 0.40 A, r = 8.0 cm = 8.0 x 10⁻² m B = fracμ₀ nI2 r = frac4 π × 10⁻⁷ × 100 × 0.42 × 8 × 10⁻² = π x 10^(-4 )T 1
- What do you mean by the steady current? A steady current is that in which the intensity of current remains constant. 1
- What do you mean by the varying current? A varying current is the one in which the intensity of current does not remain constant. 1
- Why does current become a scalar quantity? Currently does not obey vector addition principle, i.e., the sum of currents always remains the same, whatever be the angle between conducto... 1
- The free electrons inside a metallic conductor are in random motion. Can we detect current in the conductor? No. In random motion, the average velocity is zero. 2
- What is the essential condition for current flow in a conductor? When a potential difference is applied across the conductor, an electric field is set up and electrons begin to make directed flow and hence... 1