Advertisements
Advertisements
Question
Rewrite the following statement by selecting the correct option:
1 A = ____________ mA.
Options
102
10-2
103
10-3
Advertisements
Solution
1 A = `10^3` mA.
APPEARS IN
RELATED QUESTIONS
Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V.
Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
Write Joule's law of heating.
An electric kettle rated at 220 V, 2.2 kW, works for 3 hours. Find the energy consumed and the current drawn.
A resistance of 25 Ω is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.
Name the material which is used for making the filaments of an electric bulb.
An electric fuse works on the:
(a) chemical effect of current
(b) magnetic effect of current
(c) lighting effect of current
(d) heating effect of current
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.
Heat energy is being produced in a resistance in a circuit at the rate of 100 W. The current of 3 A is flowing in the circuit. What must be the value of the resistance?
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.
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.
Why does tungsten metal used to make solenoid type coil in an electric bulb?
Give scientific reason :
In the electric equipment producing heat e.g. iron, electric heater, boiler, toaster, etc., an alloy such as Nichrome is used, not pure metals.
Write the mathematical expression for Joule’s law of heating.
Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.
These days when current in the circuit suddenly increases _______ switches are used.
A coil of an alloy _______ is used in electric heater cooker as a resistor.
What is overloading?
Write scientific reason.
A coil made up of alloy Nichrome is used in the electric heater cooker as a resistor.
Name any two appliances which works on the phenomenon of heating effect of electric current.
What does overloading cause?
True or False – If False give the correct answer
The fuse wire does not melts whenever there is overload in the wiring.
Define fuse.
An electric iron draws a current of 4 A when connected to 220 V mains. Its resistance must be:
(a) Observe the diagram given below and state whether the bulb will glow or not when we switch on K.
(b) Is it safe to handle the bulb when the switch is OFF?
(c) Give a reason for your answer in (b).
Unscramble the following words:
SFEU
Can we use the same fuse in a geyser and a television set? Explain.
Paheli took a wire of length 10 cm. Boojho took a wire of 5 cm of the same material and thickness. Both of them connected the wires as shown in the circuit given in the following figure. The current flowing in both the circuits is the same.
- Will the heat produced in both cases be equal? Explain.
- Will the heat produced be the same if the wires taken by them are of equal lengths but of different thickness? Explain.
Fuse is a strip of alloy wire which is made up of lead and tin with a very low ______.
Match the following
| 1. | Bulb | a. | Conductor |
| 2. | Electroplating | b. |
Insulator |
| 3. | Pure water | c. | Heating effect of current |
| 4. | Salt solution | d. | Chemical effect of current |
Assertion: A current-carrying wire should be charged.
Reason: The current in a wire is due to the flow of free electrons in a definite direction.
Name the effect of the current responsible for the glow of the bulb in an electrical circuit.
Define the following:
Electrolyte
An electric kettle of 2 kW is used for 2h. Calculate the energy consumed in
- kilowatt hour and
- joules.
An electric iron is rated 220 V, 2 kW. If the iron is used for 3h daily find the cost of running it for one week if it costs ₹ 4.25 per kWh.
