physics

An electron of charge 1.6 x 10^-19C is accelerated between two metal plates. If the kinetic energy of the electron is 4.8 x 10^-17J, the potential difference between the plate is?

A. 30V B. 40V C. 300V D. 400V Correct Answer: Option C - 300V Explanation In general, if a charged…

4 years ago

A wire of 5Ω resistance is drawn out so that its new length is two times the original length. If the resistivity of the wire remains the same and the cross-sectional area is halved, the new resistance is?

A. 40Ω B. 20Ω C. 10Ω D. 5Ω Correct Answer: Option B - 20Ω

4 years ago

The operation of an optical fibre is based on the principal of?

A. dispersion of light B. interference of light C. refraction of light D. polarization of light Correct Answer: Option C…

4 years ago

A positive charged rod X is brought near as uncharged metal sphere Y and is then touched by a finger with X still in place. When the finger is removed; the result is that y has

A. no charge and a zero potential B. a positive charge and zero potential C. a negative charge and positive…

4 years ago

If 1.2 x 10^6J of heat energy is given off in 1 sec from a vessel maintained at a temperature gradient of 30Km−¹; the surface area of the vessel is?

A. 1.0 x 102m2 B. 9. 0 x 102m2 C. 1.0 x 103m2 D. 9.0 x 104m2 Correct Answer: Option…

4 years ago

A 2000W electric heater is used to heat a metal object of mass 5kg initially at 10°C. If a temperature rise of 30°C is obtained after 10min; the heat capacity of the material is?

A. 6.0 x 104JC-1 B. 4.0 x 104JC-1 C. 1.2 x 104JC-1 D. 8.0 x 104JC-1 Correct Answer: Option A…

4 years ago

If the distance from a point source of sound is doubled; by what factor does the intensity decrease?

A. 4.00 B. 2.00 C. 0.50 D. 0.25 Correct Answer: Option A - 4.00 Explanation In general, the intensity of…

4 years ago

At what position will an object be placed in front of a concave mirror in order to obtain an image at infinity?

A. At the pole of the mirror B. At the principal focus C. at the center of the curvature D.…

4 years ago

The phenomenon where by the water droplets in the atmosphere combines with dust particles in the air to reduce visibility is?

A. cloud B. mist C. hail D. fog Correct Answer: Option D - fog

4 years ago

If an object is placed between two parallel plane mirrors with their reflecting surfaces facing each other; how many images of the object will be formed?

A. Infinite B. Eight C. Four D. Two Correct Answer: Option A - Infinite Explanation The number of images to…

4 years ago
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