The number of photons of wavelength of 540 nm emitted per second by an electric bulb of power 100 W is (given h=6×10⁻³⁴ J-s)
Options
(a) 100 (b) 1000 (c) 3×10²⁰ (d) 3×10¹⁸
Correct […]
Two identical cells of the same e.m.f. and same internal resistance give the same current through an external resistance of 2 Ω, regardless of whether they are connected in series or in parallel. The internal […]
The unit of specific conductivity is
Options
(a) Ohm⁻¹ cm⁻¹ (b) Ohm cm⁻² (c) Ohm-cm (d) Ohm⁻¹ cm⁻²
Correct Answer:
Ohm⁻¹ cm⁻¹
Explanation:
No explanation available. Be the first to write the explanation […]
Dimensional formula for electrical resistance R is given by
Options
(a) [M¹L²T⁻³I⁻²] (b) [ML²T⁻³I⁻²] (c) [ML²T³I⁻²] (d) [ML²T³I²]
Correct Answer:
[M¹L²T⁻³I⁻²]
Explanation:
No explanation available. Be the first to write the explanation for […]
Alternating current is transmitted to distant places at
Options
(a) Low voltage and high current (b) Low voltage and low current (c) High voltage and high current (d) High voltage and low current
A proton of mass 1.6×10⁻²⁷ kg goes round in a circular orbit of radius 0.10 m under a centripetal force of 4×10⁻¹³ N. The frequency of revolution of the proton is about
Options
Cathode rays are produced when the pressure is of the order of
Options
(a) 2 cm of Hg (b) 0.1 cm of Hg (c) 0.01 mm of Hg (d) 1μm of Hg
Correct […]
The escape velocity of a body on an imaginary planet which is thrice the radius of the earth are double the mass of the earth (Ve is the escape velocity from the earth)
Options […]
The coefficient of friction between the tyres and the road is 0.25. The maximum speed with which a car can be driven round a curve of radius 40 m without skidding is (assume g=10 ms⁻²) […]
A ballet dancer, dancing on smooth floor, is spinning about a vertical axis with her arms folded with an angular velocity of 20 radian/sec. When she stretches her arms fully, the spinning speed decreases to […]
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