physics

The main reason why a.c. is transmitted at very high voltage and low current is that?

A. flows faster through the conductor B. can be stepped down C. is cheaper to generate D. reduces heat loss…

6 years ago

A lamp rated 100W, 240V is lit for 5hours. Calculate the cost of lighting the lamp if 1kWh of electrical energy cost N5.

A. N2.50 B. N3.20 C. N6.50 D. N9.60 Correct Answer: Option A A. N2.50 Explanation Power = 100W; Voltage =…

6 years ago

A transformer connected to a 240Vr.m.s has 3000 turns in its primary coil and 500 turns in its secondary coil. Calculate the output voltage.

A. 4000V B. 400V C. 40V D. 4V Explanation Np=3000turns Ns=500turns Ep=240Vr.m.s Es=? Ns/Np=Es/Ep 500/3000=Es/240 ⟹Es=240×500/3000=40V

6 years ago

Which of the following statements is/ are correct?

I. Gravitational potential due to a mass at a point a distance r away is proportional to r² II. Gravitational…

6 years ago

A circuit is set up as shown in the diagram below. When the key is closed, the ammeter reading will be?

  A. 6A B. 4A C. 2A D. 1A Correct Answer: Option C Explanation The resistors are connected both in…

6 years ago

Which of the following objects is not a conductor of electricity?

A. The Earth B. Human body C. Iron rod D. Dry wood Correct Answer: Option D D. Dry wood Explanation…

6 years ago

The force per unit charge experienced at a point in a field is the?

A. gravitational field strength B. electric potential C. electric field intensity D. magnetic field strength Correct Answer: Option C D.…

6 years ago

The inverse of the time required for a wave to complete one full cycle is called?

A. wavelength B. period C. frequency D. amplitude Correct Answer: Option C C. frequency Explanation The time required to complete…

6 years ago