Advertisements
Advertisements
प्रश्न
Write down the formula for the heat produced when a current I is passed through a resistor R for time t.
Advertisements
उत्तर
H = I2Rt where H is the heat energy produced, I is the current, R is the resistance and t is the time.
APPEARS IN
संबंधित प्रश्न
Why is the tungsten used almost exclusively for filament of electric lamps?
Name any two effects of electric current.
An electric room heater draws a current of 2.4 A from the 120 V supply line. What current will this room heater draw when connected to 240 V supply line?
What is nichrome? State its one use.
An electric kettle rated at 220 V, 2.2 kW, works for 3 hours. Find the energy consumed and the current drawn.
The electrical resistivities of four materials P, Q, R and S are given below:
| P | `6.84xx10^8`Ωm |
| Q | `1.70xx10^8`Ωm |
| R | ` 1.0xx10^15`Ωm |
| s | `11.0xx10^-7`Ωm |
Which material will you use for making: (a) heating element of electric iron (b) connecting wires of electric iron (c) covering of connecting wires? Give reason for your choice in each case.
Give Scientific reason.
In practice, the unit kWh is used for the measurement of electrical energy, rather than joule.
Solve the following example.
Two tungsten bulbs of wattage 100 W and 60 W power work on 220 V potential difference. If they are connected in parallel, how much current will flow in the main conductor?
Statement 1 : Electric current ( flow of electrons ) creates heat in the resistor.
Statement 2 : Heat in the resistor is created according to the rule of energy conservation.
Explain Statement 1 with the help of Statement 2.
Answer the following question:
what is the heating effect of the electric current? state any four applications of it?
Answer the following question.
Write the mathematical expression for Joule's law of heating.
Which of the following substance contracts on heating?
Define fuse.
Mark the correct choice
- Assertion: Electric appliances with a metallic body have three wire connections.
- Reason: Three-pin connections reduce the heating of the connecting wires.
How does use of a fuse wire protect electrical appliances?
Name two electric devices for each where
- heating effect of current is used and
- magnetic effect of current is used.
An MCB can be used instead of a fuse in an electrical circuit.
Explain the working of an electric fuse.
State the law that explains the heating effect of current with respect to the measurable properties in an electrical circuit.
When a current I flows through a wire of resistance R for time t then the electrical energy produced is given by ______.
