physics

When an alternating current given by I = 10sin (120π)t passes through a 12Ω resistor; the power dissipated in the resistor is?

A. 1200W B. 600W C. 120W D. 30W Correct Answer: Option A - 1200W Explanation An a.c current is usually…

4 years ago

The maximum kinetic energy of the photoelectron emitted from a metal surface is 0.34eV. If the work function of the metal surface is 1.83eV; find the stopping potential?

A. 2.17V B. 1.49V C. 1.09V D. 0.34V Correct Answer: Option D - 0.34V Explanation The stopping potential is the…

4 years ago

The force on a charge moving with velocity v in a magnetic field B is half of the maximum force when the angle between v and B is?

A. 90° B. 45° C. 30° D. 0° Correct Answer: Option C - 30° Explanation The force on a moving…

4 years ago

A circuit has an area of 0.4m² and consists of 50 loops of wire. If the loops are twisted and allowed to rotate at a constant angular velocity of 10 rads−¹ in a uniform magnetic field of 0.4T, the amplitude of the induced voltage is

A. 8V B. 16V C. 20V D. 80V Correct Answer: Option D - 80V Explanation The induced voltage = time…

4 years ago

The count rate of radioactive material is 800 count/min. If the half-life of the material is 4 days, what would the count rate be in 16 days later?

A. 200 count / min B. 100 count / min C. 50 count / min D. 25 count / min…

4 years ago

A ray incident on a glass prism undergoes minimum deviation when the?

A. incident angle is equal to the angle of refraction B. refraction angle equals 90° C. incident angle equals 90°…

4 years ago

The most suitable cell used for short interval switches in electric bells is a?

A. lead-acid accumulator B. Daniel cell C. Leclanche cell D. nickel-iron accumulator Correct Answer: Option C - Leclanche cell

4 years ago

Which of the following pairs of light rays show the widest separation in the spectrum of white light?

A. Blue and Red B. Green and Yellow C. Indigo and Violet D. Orange and Red Correct Answer: Option A…

4 years ago

Which combination of the below makes iron preferable to steel in the making of electromagnets?

I. It retains its magnetic much longer than steel. II. It is more easily magnetized than steel III. It is…

4 years ago

A magnetic field is said to exist at a point if a force is?

A. exerted on a stationary charge at the point B. exerted on a moving charge at the point C. deflected…

4 years ago
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