physics

What is the best method of demagnetizing a steel bar magnet?

A. Hammering B. Heating it C. Rough handling it D. Solenoid method Correct Answer: Option D - Solenoid method

5 years ago

PHCN measures its electrical energy in?

A. W B. KWh C. Wh D. J Correct Answer: Option B - KWh

5 years ago

A circuit has a resistance of 200Ω. The resistance of the circuit can be reduced to 120Ω when?

A. A 300Ω resistor is connected to it in parallel B. An 80Ω resistor is connected to it in series…

5 years ago

If a metal wire 4m long and cross-sectional area 0.8 mm² has a resistance of 60; find the resistivity of the wire?

A. 5.3x10^-7 B. 3.0x10^-5 C. 1.2x10^-6 D. 3.2x10^-6 Correct Answer: Option C - 1.2x10^-6 Explanation P=RA/l (Ωm) P=6×0.8/4 (Ωm) P=1.2×10^−6Ωm

5 years ago

The maximum power transfer occur in a cell when the external resistance is?

A. Twice the internal resistance of the cell B. The same as the internal resistance of the cell C. Greater…

5 years ago

What charge is stored in a 0.1F capacitor when a 10V supply is connected across it?

A. 1C B. 5C C. 4C D. 2C Correct Answer: Option A - 1C Explanation Q = CV = 0.1…

5 years ago

When a negatively charged rod is brought near the cap of a charged gold leaf electroscope which has positive charges, the leaf?

A. Remains the same B. Collapses C. Collapses and diverges again D. Diverges Correct Answer: Option B - Collapses

5 years ago

When a telescope is in normal use; the final image is at?

A. Infinity B. The focus C. The radius of curvature D. The near the point Correct Answer: Option A -…

5 years ago

In a compound microscope; the objective and the eye piece focal lengths are?

A. At infinity B. Long C. Short D. The same Correct Answer: Option C - Short

5 years ago

The focal length of a concave mirror is 2.0cm. If an object is placed 8.0cm from it; the image is at?

A. 2.7m B. 2.0m C. 2.3m D. 2.5m Correct Answer: Option A - 2.7m Explanation 1/U+1/V=1/f 1/8+1/V=1/2 V = 8/3…

5 years ago