Practical applications of heating effect

Q.

What is thermal resistivity?

Q.

What Is Constantan Wire?

Q. A wire of resistance 5ohm is bent in the form of a closed circle. Find the resistance between two points at the ends of any diameter of the circle.

Q.

Name the effect of current responsible for the glow of the bulb in an electric circuit.

Q.

What are the special features of heating a wire

Q.

Two light bulbs P and Q are identical in all aspects, except that P's filament is thicker than Q's. If the same potential difference is applied to each, then:

1. Q will burn brighter because it has the greater resistance.

2. P will burn brighter because it has the greater resistance.

3. Q will burn brighter because it has the lower resistance.

4. P will burn brighter because it has the lower resistance.

Q. In a series circuits one with aluminum wire and other with nichrome wire of same length and thickness.which will produce more heat for the same 6V in both circuits?

Q.

Applications of heating effect of electric current.

Q.

State energy conversion that takes place during working of Electric toaster is

1. Heat energy to Electrical energy

2. Chemical energy to Heat energy

3. Light energy to Electrical energy

4. Electrical energy to Heat energy

Q. if we pass the current for a longer time what will happen to the resistance how should we avoid it

Q. Which of the following equipment does not work on principle of Joule's law?

1. Electric Heater
2. Electric Iron
3. Electric Bulb
4. Electric Fan

Q.

Which Metal Is Used In Potentiometer?

Q. Why are alloys commonly used in electrical heating devices? Give reason.

Q. In an electrical circuit, the fuse acts as a:

1. Power multiplier
2. Voltage multiplier
3. Current multiplier
4. Safety device

Q.

Which of the following substances offer very low resistance?

1. nichrome

2. water

3. graphite

4. steel

Q. Mark the correct reason/s why nichrome is used for making heating element of electrical appliances.

1. Nichrome does not oxidize
2. Nichrome has higher resisistivity and consequently a higher resistance
3. All
4. Nichrome doesn't burn easily at high temperatures as it has higher melting and boiling point than metals

Q.

Why Earth wire are long

Q. State four most common electrical appliances based on heating effect of electric current. Why do we use finely heated platinum wire in surgery?

Q. The filament of an electric bulb is of tungsten because

1. its resistance is negligible.
2. its melting point is high.
3. it is cheaper.
4. filament is easily made.

Q. An electric iron is based upon the principle of:

1. Heating effect of current
2. Magnetic effect of current
3. None of these
4. Chemical effect of current

Q. Write daily life uses of heating effect of electric current.

Q. In electric heater:

1. Chemical energy is converted to electrical energy
2. Electrical energy is converted to chemical energy
3. Heat energy is converted to electrical energy
4. Electrical energy is converted to heat energy

Q. What are the characteristics of heating element used in electric heating device?

Q.

Why do we use tungsten filament in bulb or lamps ? [2 MARKS]

Q. An electric bulb generally uses a filament coated with

1. Platinum
2. Thorium
3. Silver
4. Radium

Q. Why are the coils of electric toasters made of an alloy rather than a pure metal?

Q. What happens on connecting too many appliances at a time to a single socket?

Q. The essential requirements for a good heating element are _________________.

1. High resistivity and high melting point
2. Low resistivity and low melting point
3. High resistivity and low melting point
4. Low resistivity and high melting point

Q. Give two advantages of heating effect of electric current.

Q. Why the cord of an electric kettle does not glow while the heating element does?