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A conducting wire of length l is turned In the form of a circular coil and a current l is passed through it. For the torque, due to magnetic field produced at its centre, to be maximum, the number of turns in the coil will be
The torque (τ) on a current-carrying coil is given by: τ = nI AB For fixed wire length l, the radius is: r = l/2πn Torque is maximized when n = 2, as the product of the number of turns and area is optimized. Answer: (B) Two For more visit here: https://www.tiwariacademy.com/ncert-solutions/class-12/Read more
The torque (τ) on a current-carrying coil is given by:
τ = nI AB
For fixed wire length l, the radius is:
r = l/2πn
Torque is maximized when n = 2, as the product of the number of turns and area is optimized.
Answer: (B) Two
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The gyro-magnetic ratio of an electron in an H-atom, according to Bohr model, is
The gyro-magnetic ratio (γ) of an electron in a hydrogen atom, according to the Bohr model, is given by: γ = e/2m It is independent of the orbit number (n) as it only depends on fundamental constants (e and m). The ratio is negative because the electron has a negative charge. Answer: (B) Negative htRead more
The gyro-magnetic ratio (γ) of an electron in a hydrogen atom, according to the Bohr model, is given by:
γ = e/2m
It is independent of the orbit number (n) as it only depends on fundamental constants (e and m). The ratio is negative because the electron has a negative charge.
Answer: (B) Negative
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See lessTwo wires of same length are shaped into a squatr and a circle if they carry same current, ratio of magnetic moment is :
Let the length of each wire be L. For a square of side a, 4a = L ⟹ a = L/4. Magnetic moment, M₁ = IA² = I L/4 ². For a circle of radius r, 2πr = L ⟹ r = L/2π. Magnetic moment, M₂ =Iπr² = Iπ L/2π ² . Ration. M₁/M₂ = 2/π. Answer: (A) 2 : π For more visit here: https://www.tiwariacademy.com/ncert-solutRead more
Let the length of each wire be L.
For a square of side a, 4a = L ⟹ a = L/4. Magnetic moment,
M₁ = IA² = I L/4 ².
For a circle of radius r, 2πr = L ⟹ r = L/2π. Magnetic moment,
M₂ =Iπr² = Iπ L/2π ² .
Ration. M₁/M₂ = 2/π.
Answer: (A) 2 : π
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Current sensitivity of a galvanometer can be increased by decreasing:
Current sensitivity of a galvanometer is given by S = nBA/K where n = number of turns, B = magnetic field, A = area of coil and k = torsional constant. To increase sensitivity, S should be maximized. Decreasing the torsional constant k increases S as they are inversely proportional. Hence, the correRead more
Current sensitivity of a galvanometer is given by
S = nBA/K
where n = number of turns, B = magnetic field, A = area of coil and k = torsional constant.
To increase sensitivity, S should be maximized. Decreasing the torsional constant
k increases S as they are inversely proportional.
Hence, the correct answer is (C) Torsional constant k.
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An electric current passes through a long straight copper wire. At a perpendicular distance 5 cm from the straight wire, the magnetic field is B. The magnetic field at perpendicular distance 20 cm from the straight wire would be
The magnetic field due to a long straight current-carrying wire is given by: B = μ0I/2πr Here, B ∝ 1/r . If the distance increases from 5 cm to 20 cm (i.e., four times), the magnetic field decreases by the same factor: B′ = B/4. Therefore, the new magnetic field is B/4. Answer: (B) B/4. For more visRead more
The magnetic field due to a long straight current-carrying wire is given by:
B = μ0I/2πr
Here, B ∝ 1/r .
If the distance increases from 5 cm to 20 cm (i.e., four times), the magnetic field decreases by the same factor:
B′ = B/4.
Therefore, the new magnetic field is B/4.
Answer: (B) B/4.
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