Tag: physics

Questions Related to physics

A substance consisting of a coil of wire with an iron core and is only magnetized when an electric current flows through it is called :

physics properties of a magnetic field let's make a magnet making magnets making and handling magnets

  1. Magnet

  2. Electromagnet

  3. Coil

  4. Battery

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Correct Option: B
Explanation:

The phenomenon of converting a substance into a magnet by flowing an electric current through a coil around it is known as electromagnetism and the magnet so formed is known as electromagnet.

All magnetic materials lose their magnetic properties when :

physics properties of a magnetic field let's make a magnet making magnets making and handling magnets

  1. Dipped in water

  2. Dipped in oil

  3. Brought near a piece of iron

  4. Strongly heated

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Correct Option: D
Explanation:
All the magnetic material lose their magnetic properties when strongly heated.
Every magnetic materials have a temperature called the curle point; above which they will lose their magnetism.
OPTION : D.

Magnets lose their properties if :

physics properties of a magnetic field let's make a magnet making magnets making and handling magnets

  1. A.C. is passed through them

  2. heated strongly

  3. dropped from a height

  4. all of the above

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Correct Option: A,B
Explanation:

When a magnet is treated above 176℉ (80)℃ magnet will quickly loose their magnetic properties. The magnet will become permanently demagnetized if exposed to those temperatures for a certain length of time.

By passing an alternating current the magnetic property can be removed because the alternating current produces a reverse magnetizing field which opposes the object magnetism.

 

A.  Ferromagnetic materials will lose their magnetism if heated above a point known as the Curie temperature.
B. You would have to re-magnetize the magnet again, either in a solenoid or with another permanent magnet, in order to restore the magnetism.
C. If you heat a magnet up a little bit, it will lose some of its magnetism, but on returning to room temperature full magnetism can be restored. 
Which among the following is/are true?

physics properties of a magnetic field let's make a magnet making magnets making and handling magnets

  1. Only A

  2. Both A and B

  3. Only C

  4. All A, B and C

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Correct Option: D
Explanation:

All the three statements are true that the ferromagnetic materials lose their magnetism on heating above the Curie temperature,

The magnet has to re-magnetized with another magnet or solenoid to restore its magnetism and the magnetism of the magnet is fully recovered when it is kept at room temperature after heating.

By which of the following activity, a magnet can loose its property?

physics properties of a magnetic field let's make a magnet making magnets making and handling magnets

  1. Excess of heating

  2. Demagnetizing magnetic field

  3. Sudden shock

  4. All of the above

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Correct Option: D
Explanation:
A magnet shows magnetic behavior because of the presence of domains which are specific formations consisting of electrons which exhibit magnetic behavior.
By all these actions, all the arranged magnetic domains which exhibit magnetic property due to their specific arrangement get rearranged and that specific formation of magnetic domain which is responsible for its magnetic behavior is destroyed.
And hence the magnet will loose its magnetic behavior.

A mixture of iron and nickel can be easily magnetized, even in a weak field. Which results in the formation of a ________. Fill in the blank.

physics properties of a magnetic field let's make a magnet making magnets making and handling magnets

  1. Permanent Magnet

  2. Electromagnet

  3. Temporary Magnet

  4. None of the above

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Correct Option: C
Explanation:

A mixture of iron and nickel is magnetized by applying an external magnetic field. This convert the mixture into a temporary magnet for the time when the field has been applied.

A magnet can induce magnetism in

physics properties of a magnetic field let's make a magnet making magnets making and handling magnets

  1. brass

  2. aluminium

  3. glass

  4. steel

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Correct Option: A
Explanation:

As the magnet can include the magnetism is femo magnetic materials.

Only, Brass is a I.M material.

Soft iron pieces are placed across the ends of bar magnets when stored. Such pieces are called :

physics fun with magnets let's make a magnet making magnets making and handling magnets

  1. preservatives

  2. keepers

  3. compasses

  4. poles

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Correct Option: B
Explanation:

Soft iron pieces are placed across the ends of bar magnets when stored; such pieces are called magnetic keepers. If the two magnets are placed side by side there will be mutual repulsion or attraction that weakens the magnetic strength. So magnets are placed side by side with opposite poles near to each other.

For a resistance R and capacitance C in series the impedence is twice that of a parallel combination of the same elements.The frequency of the applied emf shall be.

physics electric current through conductors combination of resistors combination of cells combinations of components

  1. $\dfrac{{2\pi }}{{Rc}}$

  2. $\dfrac{1}{{2\pi {R _1}c}}$

  3. $\dfrac{{2\pi }}{{\sqrt {RC} }}$

  4. $\dfrac{1}{{2\pi \sqrt {RC} }}$

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Correct Option: A

Two non ideal batteries are connected in series. Consider the following statements
(A) The equivalent emf is larger than either of the two emfs.
(B) The equivalent internal resistance is smaller than either of the two internal resistances.

physics electric current through conductors combination of resistors combination of cells combinations of components

  1. Both A and B are correct

  2. A is correct but B is wrong

  3. B is correct but A is wrong

  4. Both A and B wrong

Show answer
Correct Option: B
Explanation:

If we add two non ideal batteries in series then
so in case (a) the equivalent e.m.f.  may be larger than either of two e.m.f., but in case (b) the equivalent e.m.f. may be smaller than either of two e.m.f.
In series total resistance is always greater than individual resistance, whether batteries are connected in any way 

[i.e. either according to case (a) or case (b)].