Electricity
Practice Electricity MCQs from Physics — Science.
A house has five 40W lamps and two 100W fans. If everything runs for 10 hours a day, calculate the cost for April (30 days) at Rs 8 per unit.
Two wires of the same material have lengths in ratio 1:2 and diameters in ratio 2:1. The ratio of their resistances is:
What is the equivalent resistance between points A and B if three 6-Ohm resistors form a triangle?
A step-up transformer has a turns ratio of 1:20. If the primary current is 10A, what is the secondary current (assume 100% efficiency)?
Find the heat produced in 1 minute by a heater of 20 Ohms resistance through which 5 A current flows.
What is the current in a circuit containing a 12V battery and three 4-Ohm resistors connected in parallel?
A generator produces a voltage of 240V and delivers a current of 50A. If the resistance of the transmission line is 0.5 Ohm, how much power is lost in the line?
How much work is done to move a 2mC (millicoulomb) charge across a potential difference of 5V?
Two resistors of 30Ω and 60Ω are connected in parallel and this combination is connected to a 30V battery. What is the current through the 30Ω resistor?
A motor is 80% efficient and is supplied with 2kW. How much mechanical power does it output?
Which of the following describes the relationship for an ideal step-up transformer?
An electric kettle rated 1.5kW, 220V is used for 4 minutes to boil water. How much energy is consumed in Joules?
In a given circuit, if the voltage is tripled and resistance is doubled, the current will change by a factor of:
A galvanometer with a resistance of 100 Ohms gives full scale deflection for a current of 1mA. How much series resistance is needed to convert it into a voltmeter of range 0-10V?
What happens to the magnetic field at the center of a circular coil if its radius is doubled (keeping current and turns same)?
A solenoid of length 0.5m has 500 turns. If 2A current flows, calculate the magnetic field strength (take μ₀ = 4π x 10^-7 T m/A).
Which of the following will not change the direction of rotation of a DC motor?
What is the total energy consumed in Joules by a 100W bulb in 24 hours?
How many 60W bulbs can be safely used on a 220V circuit with a 5A fuse?
A wire is bent into a circle. What is the equivalent resistance across the diameter if the original wire had resistance R?