7th Grade > Physics
ELECTRIC CURRENT AND ITS EFFECTS MCQs
Total Questions : 113
| Page 6 of 12 pages
Answer: Option A. -> True
:
A
Electromagnets are temporary magents. The strength of an electromagnet can be varied by varying the current in the circuit. Electromagnets can be used to separate magnetic materials from the junk. In cranes, electromagnets are used to lift heavy loads.
:
A
Electromagnets are temporary magents. The strength of an electromagnet can be varied by varying the current in the circuit. Electromagnets can be used to separate magnetic materials from the junk. In cranes, electromagnets are used to lift heavy loads.
Answer: Option A. -> True
:
A
Strong electromagnets are often used in areas of heavy industry to move large pieces of iron or steel. They are commonly employed in junkyards where a crane with a huge electromagnet is used to pick up, move and drop old junk cars.
:
A
Strong electromagnets are often used in areas of heavy industry to move large pieces of iron or steel. They are commonly employed in junkyards where a crane with a huge electromagnet is used to pick up, move and drop old junk cars.
Answer: Option A. -> True
:
A
In our homes, all the electrical wires are usually covered with a layer of insulation for safety. A live wire without insulation can give an electric shock. An electric shock can be hazardous to health and sometimes it can lead to death.
:
A
In our homes, all the electrical wires are usually covered with a layer of insulation for safety. A live wire without insulation can give an electric shock. An electric shock can be hazardous to health and sometimes it can lead to death.
Answer: Option B. ->
battery
:
B
:
B
A battery is defined as a container consisting of one or more cells, in which chemical energy is converted into electricity and used as a source of power.
Answer: Option B. ->
H.C. Oersted
:
B
:
B
Hans C. Oersted was a Danish physicist and chemist who discovered that electric currents create magnetic fields. This was the first instance to know about the connection between electricity and magnetism.
Answer: Option B. ->
short circuit
:
B
:
B
The contact of live and fuse wire in a circuit is called short-circuiting. There is no current flow in this case.
Answer: Option C. ->
magnetic effect of electric current
:
C
:
C
When electric current is passed through a conductor it behaves like a magnet. It is called an electromagnet. Working of an electromagnet is based on the magnetic effects of electric current.
Answer: Option B. ->
False
:
B
The long line in the symbol of an electric cell represents its positive terminal and the short line represents its negative terminal.
:
B
The long line in the symbol of an electric cell represents its positive terminal and the short line represents its negative terminal.
Answer: Option C. ->
heating effect
:
C
When an electric bulb is connected to a power source, electric current flows through the circuit. Flow of an electric current in a conductor generates a lot of heat due to the collisions between electrons and atoms. When current flows through the filament, it generates both heat and light. This happens due to the heating effect of electric current.
:
C
When an electric bulb is connected to a power source, electric current flows through the circuit. Flow of an electric current in a conductor generates a lot of heat due to the collisions between electrons and atoms. When current flows through the filament, it generates both heat and light. This happens due to the heating effect of electric current.
Answer: Option B. ->
Silver
:
B
:
B
Metals are generally good conductors of electricity. Silver being a metal possesses this property. Infact it is the best conductor of electricity among metals. Wood, rubber and plastic do not possess the property of conducting electricity.
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