An iron rod of volume 10⁻⁴ m³ and relative permeability 1000 is placed inside a long solenoid having 5 turns/cm. If a current of 0.5 A is passed through the solenoid, then the magnetic moment […]
The horizontal component of earth’s magnetic field at a place is 3×10⁻⁴ T and the dip is tan⁻¹ (4/3). A metal rod of length 0.25m is placed in N-S direction and is moved at a […]
If the dipole moment of a short bar magnet is 1.25 A-m², the magnetic field on its axis at a distance of 0.5 m from the centre of the magnet is
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(a) 1×10⁻⁴ […]
The diameter of the eye ball of a normal eye is about 2.5 cm. The power of the eye lens varies from
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(a) 9 D to 8 D (b) 40 D to 32 […]
If the half-life of a material is 10 yr, then in what time, it becomes 1/4th part of the initial amount
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(a) 15 yr (b) 20 yr (c) 25 yr (d) 30 […]
If a mass of 20g having charge 3.0 mC moving with velocity 20ms⁻¹ enters a region of electric field of 80NC⁻¹ in the same direction as the velocity of mass then the velocity of mass […]
If two charges +4e and +e are at a distance x apart, then at what distance charge q must be placed from +e, so that it is in equilibrium?
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(a) x/2 (b) x/3 […]
Which one of the following statements is not correct in case of a semiconductor?
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(a) Temperature coefficient of resistance is negative (b) Doping increases conductivity (c) At absolute zero temperature, it behaves […]
A wire having resistance 12Ω is bent in the form of an equilateral triangle. The effective resistance between any two corners of the triangle will be
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(a) 6Ω (b) 8/3Ω (c) 9Ω (d) […]
When current I is flowing through a conductor, the drift velocity is v. If the value of current through the conductor and its area of cross-section is doubled, then new drift velocity will be
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