Advertisements
Advertisements
प्रश्न
Find the odd one out and give its explanation.
पर्याय
Tungsten
Nichrome
Aluminium
Iron
Advertisements
उत्तर
Nichrome
Explanation-
Nichrome is an alloy used for making wires, while others are soft metals.
APPEARS IN
संबंधित प्रश्न
Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V.
An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
How does the resistance of a wire vary with its area of cross-section?
An electric heater is connected to the 230 V mains supply. A current of 8 A flows through the heater.
(a) How much charge flows around the circuit each second?
How does the resistance of a wire vary with its:
diameter?
Why is a series arrangement not used for connecting domestic electrical appliances in a circuit?
An electric iron of resistance 20 ohms draws a current of 5 amperes. Calculate the heat produced in 30 seconds.
Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.
How much heat will an instrument of 12 W produce in one minute if it is connected to the heat produced by it?
The heat produced by passing an electric current through a fixed resistor is proportional to the square of:
(a) magnitude of resistance of the resistor
(b) temperature of the resistor
(c) magnitude of current
(d) time for which current is passed
The heat produced in a wire of resistance 'x' when a current 'y' flows through it in time 'z' is given by:
(a) x2 × y × z
(b) x × z × y2
(c) y × z2 × x
(d) y × z × x
Give a scientific reason:
For electric power transmission, copper or aluminium wire is used.
An electric iron of 1100 W is operated for 2 hrs daily. What will be the electrical consumption expenses for that in the month of April? (The electric company charges Rs 5 per unit of energy).
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.
Rewrite the following statement by selecting the correct option:
1 A = ____________ mA.
Answer the following question:
what is the heating effect of the electric current? state any four applications of it?
The ‘live’ and the ‘neutral’ wires have potential difference of _______.
These days when current in the circuit suddenly increases _______ switches are used.
Right or wrong sentence.
Live wire and neutral wires have a 220 V potential difference.
Explain the importance/uses of fuse wire.
Define fuse.
An electric bulb is connected to a 220 V generator. The current is 0.50 A. What is the power of the bulb?
When a switch is in OFF position,
- circuit starting from the positive terminal of the cell stops at the switch.
- circuit is open.
- no current flows through it.
- current flows after some time.
Choose the combination of correct answer from the following.
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.
An MCB can be used instead of a fuse in an electrical circuit.
An electric fuse has a body made of ceramic and two points for connecting the fuse wire.
Explain the working of an electric fuse.
Copper wire offers very little ______ and does not get heated up quickly.
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 |
Name the effect of the current responsible for the glow of the bulb in an electrical circuit.
A student boils water in an electric kettle for 20 minutes. Using the same mains supply he wants to reduce the boiling time of water. To do so should he increase or decrease the length of the heating element? Justify your answer.
Define the following:
Electrolyte
Find the odd one out.
In which of the following applications of Iron, rusting will occur most? Support your answer with valid reason.
| A | B | C | D |
 |
 |
 |
 |
In a set up the students coated iron nails with zinc metal and noted that, iron nails coated with zinc prevents rusting. They also observed that zinc initially acts as a physical barrier, but an extra advantage of using zinc is that it continues to prevent rusting even if the layer of zinc is damaged. Name this process of rust prevention and give any two other methods to prevent rusting.
What is the heating effect of electric current?
