Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice electrostatic and magnetic analogy magnetism and matter magnetic effects of current and magnetism physics

Two magnetic poles have their strengths in the ratio 3 : 2. They are kept at a distance of 0.6 m in air and the force of repulsion is found to be 0.06 dynes. The pole strengths are (in amp. m)

  1. 1.8, 1.2

  2. 18, 12

  3. 6, 4

  4. 0.6, 3.6
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$1 dyne = 10^{-5}$
$\mu _{0}=4\pi \times 10^{-7}TmA^{-1}$ 
$m _{1}=3m$
$m _{2}=3m$
$F=\dfrac{\mu _{0}m _{1}\times m _{2}}{4\pi \times r^{2}}$ r=0.6m
$0.06\times 10^{-5}=\dfrac{4\pi \times 10^{-7}\times 3m\times 2m}{4\pi \times (0.6)^{2}}$
$m^{2}=(0.6)^{2}$
$m=0.6$
$m _{1}=1.8$
$m _{2}=1.2$




Multiple choice physics effects of electric current precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

Wires used in homes are usually covered with materials like plastic or rubber. This is done to

  1. Prevent rusting

  2. Make handling easier

  3. Prevent shocks & short circuits

  4. Make them look beautiful
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Insulators are used in electrical equipment to support and separate electrical conductors without allowing current through themselves.

therefore it prevent us from shocks and short circuits.

Multiple choice physics effects of electric current precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

State whether given statement is True or False
Earth connection saves the user from electric shocks.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The current takes the path that is having less resistance . Hence lesser the resistance higher the current and higher the resistance lower the current. So in case of shock current passes though you. A normal person have a resistance of about $10\times 10^3\Omega $ and as there is no different path for the current to move hence its passes to ground though you.  

but in case a earth connection the current have almost no resistance path through the ground wire to the ground.
Therefore it helps in saving the user from electric shocks. 

Multiple choice physics effects of electric current precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

All wires used in electric circuits should be covered with

  1. a coloured material

  2. an insulating material

  3. a conducting material

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

he most important reason why electrical wires are covered in insulating material is to protect people from electrical shock, and  protection from short circuit.

Multiple choice physics effects of electric current precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

State whether given statement is True or False.
We must not touch electric switches with bare hands.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is not in general sense, but for protection purpose from any kind of defect in the insulator material damage in the electrical switch we must not touch it withh bare hands specially in case our hands are wet.

Multiple choice physics effects of electric current precaution with the electrical circuit precautions to be taken while dealing with current devices used to protect from shock of electric current

A person may get a severe electric shock on touching a :

  1. a neutral wire

  2. a live wire

  3. an earth wire

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A person may get a severe electric shock on touching the live wire. Because live wires have high potential and current flows through our body (low potential ). Thus we get electric shocks.