A cell of internal resistance r supplies current to a 6.0Ω resistor and its efficiency is 75%. Find the value of r.

5 years ago

A. 4.5Ω B. 1.0Ω C. 8.0Ω D. 2.0Ω Correct Answer: Option D = 2.0Ω Explanation Efficiency = power out put/power…

A gas with initial volume of 2 X 10^-6 m³ is allowed to expand to six times its initial value at constant pressure of 2 x 10^5Nm−². The work done is?

5 years ago

A. 2.0J B. 4. 0J C. 12.0J D. 2.4J Correct Answer: Option D = 2.4J Explanation P = F/A =>…

A string is fastened tightly between two walls 24cm apart. The wavelength of the second overtone is?

5 years ago

A. 24cm B. 16cm C. 12cm D. 8cm Correct Answer: Option B - 16cm Explanation For a string fixed at…

A plane sound wave of frequency 85.5Hz and velocity 342ms−¹ is reflected from a vertical wall. At what distance from the wall does the wave have antinode?

5 years ago

A. 2m B. 4m C. 1m D. 3m Correct Answer: Option C = 1m Explanation If F = 85.5Hz, V…

The thermometric substance of an absolute thermometer is?

5 years ago

A. alcohol B. mercury C. helium D. platinum Correct Answer: Option B - mercury Explanation Mercury is the “liquid of…

The pressure of a given mass of a gas changes from 200Nm−² to 120Nm−² while the temperature drops from 127°C to -73°C. The ratio of the final volume to the initial volume is?

5 years ago

A. 2 : 5 B. 5 : 4 C. 5 : 2 D. 4 : 5 Correct Answer: Option B…

The driving mirror of a car has a radius of curvature of 1m. A vehicle behind the car is 4m from the mirror. Find the image distance behind the mirror?

5 years ago

A. 8/7 B. 4/9 C. 9/2 D. 4/7 Correct Answer: Option B - 4/9 Explanation A driving mirror is always…

The terrestrial telescope has one extra lens more than the astronomical telescope. The extra lens is for?

5 years ago

A. improving the sharpness B. creating an inverted image C. magnification of the image D. erection of the image Correct…

A ray of light strikes a plane mirror at an angle of incidence of 35°. If the mirror is rotated through 10°; through what angle is the reflected ray rotated?

5 years ago

A. 70° B. 45° C. 25° D. 20° Correct Answer: Option D = 20° Explanation Whenever a ray of light…

Ice cubes are added to a glass of warm water. The glass and water are cooled by?

5 years ago

A. conduction only B. convection only C. conduction and convection D. convection and radiation Correct Answer: Option C - conduction…

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