Moving Charges & Magnetism Worksheets
Worksheet4.02
(Magnetic Field Due To A Straight Current Carrying Conductor)
General Instructions
Magnetic Field Due To A Straight Current Carrying Conductor
CBSE, NEET, PSEB, HSEB etc.

Ques01:
A straight wire carries a current of 3 A. Calculate the magnitude of the magnetic field at a point 10 cm away from the wire.
(CBSE D 1996)
Ques02:
At what distance from a long straight wire carrying a current of 12 A will the magnetic field be equal to 3 x 10^{5} T?
Ques03:
Current flows due north in a horizontal transmission line. Predict the direction of magnetic field at a point vertically above it.
Ques04:
The figure shows two long current carrying wires A and B. Find the magnitude and direction of the magnetic field at points P, Q and R.
Ques05:
Two long parallel wires are placed at a distance of 16 cm from each other in air. Each wire has a current of 4 A. Calculate the magnetic field at midpoint between them when the currents in them are
(i) in the same direction
(ii) in the opposite directions
Ques06:
Two parallel long wires carry currents I_{1} and I_{2} with I_{1} > I_{2}. When the currents are in the same direction, the magnetic field at a point midway between the wires is 10 μT. If the direction of I_{2} is reversed, the field becomes 30 μT. Calculate the ratio of I_{1} and I_{2}.
Ques07:
Two long straight wires A and B placed parallel to each other at a separation of 6 cm carry currents as shown. Find the point on the line AB where the resultant magnetic field is zero.
Ques08:
Two long straight wires A and B placed parallel to each other at a separation of 6 cm carry currents as shown. Find the point on the line AB where the resultant magnetic field is zero.
Ques09:
What will be the resultant magnetic field at origin due to the given four infinite length wires if each wire produces a magnetic field B at the origin?
Ques10:
Find the magnetic field at point P due to the given current distribution
Ques11:
Two infinitely long insulated wires are kept perpendicular to each other. They carry currents as shown.
(i) Find the magnitude and direction of the magnetic field at point P.
(ii) If the direction of current is reversed in one of the wires, what would be the magnitude of the field?
Ques12:
Two insulating infinitely long conductors carrying currents I_{1} and I_{2} lie mutually perpendicular to each other in the same plane as shown. Find the magnetic field at the point P (a,b).
Ques13:
Two semiinfinitely long straight current carrying conductors are held at right angles to each other so that their common end lies at the origin as shown. If both the conductors carry the same current I as shown, find the magnetic field at the point P (a,b).
Ques14:
Two insulating infinitely long conductors carrying currents I_{1} and I_{2} lie mutually perpendicular to each other in the same plane as shown. Find the locus of the point at which the net magnetic field is zero.
Ques15:
Two infinite length wires carries currents 8 A and 6 A respectively and placed along X and Y axis. Find the magnetic field intensity at a point P (0,0,d) m.
Ques16:
A wire in the form of a square of side ‘a’ carries current ‘I’ in clockwise direction. Find the magnetic field at its center.
Ques17:
Figure shows a square loop made from a uniform wire. If a battery is connected between the points A and C, what will be the magnetic field at the center of the square?
Ques18:
A wire in the form of an equilateral triangle of side ‘a’ carries current ‘I’ in anticlockwise direction. Find the magnetic field at any of its vertices.
Ques19:
A current of 1 A is flowing in the sides of an equilateral triangle of side 4.5 x 10^{2} m. Find the magnetic field at the centroid of the triangle.
(Roorkee 1991)
Ques20:
A closed circuit is in the form of a regular hexagon of side ‘a’. If the circuit carries current I, what is the magnetic induction at the center of the hexagon?
(IPUEE 2013)
ANSWER KEY
1. 6 µT
2. 8 cm
3. Due east
4. B_{P} = 20 µT ⊙ ; B_{Q} = 100 µT ⓧ ; B_{R} = 46.7 µT ⊙
5. (i) Zero (ii) 20 µT
6. 2
7. At a distance of 1.71 cm from wire B between the two wires
8. At a distance of 4 cm from wire B on its right side
9. 2√2 B
10. µ_{0}Ia / πr^{2} (î)
11. (i) 2 x 10^{5} T normally into the plane of paper (ii) zero
12. (µ_{0} / 2π)(I_{2}/b – I_{1}/a) directed outward
13. (µ_{0}I / 4πab){(√(a^{2} + b^{2}) + a + b }
14. y = (I_{2}/I_{1})x
15. 5µ_{0} / πd
16. 2√2µ_{0}I / πa ⓧ
17. Zero
18. µ_{0}I / 2√3πa ⊙
19. 40 µT
20. √3µ_{0}I / πa
MCQs Quiz
Quiz on Magnetic Field Due To Straight Current Carrying Conductor
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