Electricity
Practice Electricity MCQs from Physics — Science.
A wire has resistance R. If its radius is doubled, what will be its new resistance?
Which of these provides the most energy-efficient lighting?
What is the purpose of using a soft iron core in an electromagnet?
If four 100W bulbs are used for 5 hours every day, how many units of electricity are consumed in 1 day?
Which device is used to maintain a constant current by varying resistance?
If a circuit is powered by 220V and the current is 0.2A, what is the power consumed in Watts?
A wire of resistance R is stretched to double its original length while keeping volume constant. What is its new resistance?
An ideal transformer has 100% efficiency. If input power is 500W and output voltage is 50V, what is the output current?
Two resistors R1 and R2 are connected in parallel. If R1 > R2, which of the following is true for the current (I1 and I2) flowing through them?
A 100W-220V bulb and a 60W-220V bulb are connected in series to a 220V supply. What is the total power consumed by the bulbs together?
Which of the following describes the efficiency of a transformer?
In a transformer, if the efficiency is 80%, input power is 1000W, and output voltage is 200V, find the output current.
If a current of 1A flows through a conductor for 1 hour, what is the total charge that passes through a cross-section?
Calculate the effective resistance of three resistors 3Ω, 6Ω, and 9Ω connected in parallel.
If the energy consumed by a 50W bulb in one month (30 days) is to be found, where it's used for 10 hours daily, how many units is it?
The potential difference across a 10 Ohm resistor is 50 V. How many electrons pass through the resistor in 2 seconds?
A wire of resistivity 'rho' is stretched so that its length increases by 10%. What is the approximate percentage increase in its resistance?
Three identical resistors are first connected in series and then in parallel. The ratio of their equivalent resistances (Series : Parallel) will be:
Lenz's Law is a consequence of the law of conservation of: