Current Electricity questions
395 published questions with worked solutions.
- Mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for...
- A copper wire is stretched to make it 0.5% longer. The percentage change in its electrical resistance if its volume remains...
- Two electric bulbs, rated at (25 W, 220 V) and (100 W, 220 V), are connected in series across a 220 V voltage source. If the 25 W...
- Two equal resistances when connected in series to a battery, consume electric power of 60 W. If these resistances are now...
- A current of 2 mA was passed through an unknown resistor which dissipated a power of 4.4 W. Dissipated power when an ideal power...
- A uniform metallic wire has a resistance of 18 Ω and is bent into an equilateral triangle. Then, the resistance between any two...
- A 2 W carbon resistor is color coded with green, black, red and brown respectively. The maximum current which can be passed...
- One kg of water, at 20ºC, is heated in an electric kettle whose heating element has a mean (temperature averaged) resistance of...
- In a building there are 15 bulbs of 45W, 15 bulbs of 100 W, 15 small fans of 10 W and 2 heaters of 1 kW. The voltage of electric...
- Two resistors 400 and 800 are connected in series across a 6 V battery. The potential difference measured by a voltmeter of 10 k...
- The current in a conductor is expressed as I = 3t^2 + 4t^3, where I is in Ampere and t is in second. The amount of electric...
- An electric bulb rated 50 W – 200 V is connected across a 100 V supply. The power dissipation of the bulb is:
- To measure the internal resistance of a battery, potentiometer is used. For R = 10 Ω, the balance point is observed at ℓ = 500 cm...
- A wire of resistance 20 Ω is divided into 10 equal parts. A combination of two parts are connected in parallel and so on. Now...
- A wire of resistance R and radius r is stretched till its radius became r/2. If new resistance of the stretched wire is xR, then...
- Four resistances of 15 , 12 , 4 and 10 respectively in cyclic order to form Wheatstone's network. The resistance that is to be...
- The series combination of two batteries, both of the same emf 10 V, but different internal resistance of 20 and 5 , is connected...
- Water boils in an electric kettle in 20 minutes after being switched on. Using the same main supply, the length of the heating...
- A battery of 3.0 V is connected to a resistor dissipating 0.5 W of power. If the terminal voltage of the battery is 2.5 V, the...
- An electrical power line, having a total resistance of 2 , delivers 1 kW at 220 V. The efficiency of the transmission line is...
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