Lengths and cross-sectional areas of three copper wires are (l, A ), (2l, A/2), (l/2, 2A)Which of these wires has least (minimum) resistance?(A) Second wire (B) First wire(C) Third wire (D) All the wires have same resistance11. ...... is Ohm’s law for good conductor.(A) V R (B) V I (C) I R (D) V 1/R12. Ohmic resistance of conductor ......(A) depends on V only. (B) depends on I only.(C) depends on V and I. (D) doesn’t depend on V or I.13. When a bar magnet is divided into two pieces,(A) both the pieces lose magnetism.(B) both the pieces behave like individual magnets.(C) both the poles get separated.(D) one piece behaves like a magnet and the other does not.14. Force acting on poles of magnet per unit magnetic field is ......(A) magnetic force (B) magnetic induction (C) pole strength (D) magnetic flux15. Intensity of magnetic field means ......(A) magnetic dipole moment per unit volume.(B) magnetic force per unit pole strength.(C) no. of magnetic field lines passing through unit area.(D) no. of magnetic field lines per unit volume.16. A current carrying loop acts like a ......(A) magnetic pole (B) magnetic substance (C) magnetic dipole (D) all of abov
Question
Lengths and cross-sectional areas of three copper wires are (l, A ), (2l, A/2), (l/2, 2A)Which of these wires has least (minimum) resistance?(A) Second wire (B) First wire(C) Third wire (D) All the wires have same resistance11. ...... is Ohm’s law for good conductor.(A) V R (B) V I (C) I R (D) V 1/R12. Ohmic resistance of conductor ......(A) depends on V only. (B) depends on I only.(C) depends on V and I. (D) doesn’t depend on V or I.13. When a bar magnet is divided into two pieces,(A) both the pieces lose magnetism.(B) both the pieces behave like individual magnets.(C) both the poles get separated.(D) one piece behaves like a magnet and the other does not.14. Force acting on poles of magnet per unit magnetic field is ......(A) magnetic force (B) magnetic induction (C) pole strength (D) magnetic flux15. Intensity of magnetic field means ......(A) magnetic dipole moment per unit volume.(B) magnetic force per unit pole strength.(C) no. of magnetic field lines passing through unit area.(D) no. of magnetic field lines per unit volume.16. A current carrying loop acts like a ......(A) magnetic pole (B) magnetic substance (C) magnetic dipole (D) all of abov
Solution
Sure, here are the answers to your questions:
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The resistance of a wire is given by the formula R = ρl/A, where ρ is the resistivity, l is the length, and A is the cross-sectional area. The third wire has the least resistance because it has the shortest length and the largest cross-sectional area.
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Ohm’s law for a good conductor is (B) V I. This means that the voltage across a conductor is directly proportional to the current flowing through it.
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The ohmic resistance of a conductor (D) doesn’t depend on V or I. It depends on the material's resistivity and the dimensions of the conductor.
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When a bar magnet is divided into two pieces, (B) both the pieces behave like individual magnets. Each piece will have its own north and south pole.
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The force acting on poles of a magnet per unit magnetic field is (C) pole strength.
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Intensity of magnetic field means (B) magnetic force per unit pole strength.
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A current carrying loop acts like a (C) magnetic dipole. It has a north and a south pole and creates a magnetic field.
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