physics

Which of the following metals will provide the greatest shield against ionizing radiation?

A. Iron B. Manganese C. Alminium D. Lead Correct Answer: Option D - Lead

4 years ago

The primary coil of a transformer has N turns and is connected to a 120 V a.c. power line. If the secondary coils have 1000 turns and a terminal voltage of 1200 volts, what is the value of N?

A. 120 B. 100 C. 1000 D. 1200 Correct Answer: Option B = 100 Explanation For the transformer, V ∝…

4 years ago

The current through a resistor in an A.C circuit is given as 2 sin wt. Determine the D.C. equivalent of the current?

A. A/√2 B. 2/√A C. 2 A D. √2 A Correct Answer: Option B = 2/√A Explanation If I =…

4 years ago

Which combination of the above is true of the conduction of electricity through gases?

I. Low pressure. II. High pressure. III. High p.d. IV. Low p.d. A. I and IV only B. I and…

4 years ago

A cell can supply current of 0.4 A and 0.2 A through a 4.0Ω and 10.0Ω resistors respectively. This internal resistance of the cell is?

A. 2.0Ω B. 1.0Ω C. 2.5Ω D. 1.5Ω Correct Answer: Option A = 2.0Ω Explanation let the internal resistance of…

4 years ago

the ratio of electrostatic force FE to gravitational force FG between two protons each of charge e and mass M; at a distance d is?

A. e/4πԐoGm B.  e2/Gm2 C. Gm2/4πԐoe2 D. e2/4πԐoeGm2 Correct Answer: Option D = e2/4πԐoeGm2 Explanation Electrostatic force = FE = e2/4λEod2…

4 years ago

When a piece of rectangular glass block is inserted between two parallel capacitor; at constant plate area and distance of separation. The capacitance of the capacitor will?

A. increase B. decrease C. decrease then increase D. remain constant Correct Answer: Option A - increase

4 years ago

In a Daniel cell; the depolarizer; positive and negative electrodes are respectively?

A. copper sulphate, copper and zinc B. manganese dioxide, carbon and zinc C. sulphuric acid, lead oxide and lead D.…

4 years ago

The cost of running five 60 W lamps and four 100 W lamps for 20 hours if electrical energy cost #10.00 per kwh is?

A. 280.00 B. 160.00 C. 120.00 D. 140.00 Correct Answer: Option D - 140.00 Explanation Total power in watt =…

4 years ago

A working electric motor takes a current of 1.5A when the p.d across it is 250V. If its efficiency is 80%, the power output is?

A. 300.0W B. 469.0W C. 133.0W D. 4.8W Correct Answer: Option A Explanation Efficiency = power output/power Input => 80/100…

4 years ago
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