A long straight wire of radius a carries a steady current I. The current is uniformly distributed over its cross-section. The ratio of the magnetic field B and B’ at radial distances a/2 and 2a […]
A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil […]
A bar magnet with magnetic moment 2.5×10³ JT⁻¹ is rotating in horizontal plane in the space containing magnetic induction B=4×10⁻⁵ T. The work done in rotating the magnet slowly from a direction parallel to the […]
A vertical spring with force constant k is fixed on a table. A ball of mass m at a height h above the free upper end of the spring falls vertically on the spring so […]
A 2 kg mass starts from rest on an inclined smooth surface with inclination 30° and length 2 m. How much will it travel before coming to rest on a frictional surface with frictional coefficient […]
At what height h above earth, the value of g becomes g/2 (where R=radius of earth)?
Options
(a) (√2-1)R (b) √2R (c) (√2+1)R (d) R/√2
Correct Answer:
(√2-1)R
Explanation:
No explanation available. Be […]
Radius of orbit of satellite of earth is R. Its kinetic energy is proportional to
Options
(a) 1/R (b) 1/√R (c) R (d) 1/R³/²
Correct Answer:
1/R
Explanation:
Kinetic energy of the satellite=1/2mv₀² […]
A hollow sphere of radius 0.1m has a charge of 5×10⁻⁸C. The potential at a distance of 5cm from the centre of the sphere is (1/4πε₀=9×10⁹NM²C⁻²)
Options
(a) 4000V (b) 4500V (c) 5000V […]
A Si and a Ge diode has identical physical dimensions. The bandgap in Si is larger than that in Ge. An identical reverse bias is applied across the diodes
Options
(a) The reverse […]
B is doped in Si or Ge, then we will get
Options
(a) P-type semiconductor (b) N-type semiconductor (c) An insulator (d) A conductor
Correct Answer:
P-type semiconductor
Explanation:
No explanation available. Be […]
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