Tag: physics

Questions Related to physics

Which of the following is the purpose of an electrical cell?

physics chemical effects of electric current study about cells electric cell types of cells

  1. To change mechanical energy to electrical energy

  2. To change chemical energy to electrical energy

  3. To change electrical energy to mechanical energy

  4. To change electrical energy to chemical energy

Show answer
Correct Option: B
Explanation:

An electrical cell is an "electrical power supply" - internally it converts stored chemical energy into electrical potential energy, allowing a current to flow from the positive terminal round to the negative one via an external circuit (this is called conventional current, which is chosen to go from + to -).

State whether true or false :

Do not connect the two terminals of a cell with a single wire.

physics chemical effects of electric current study about cells electric cell types of cells

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

We should not connect the two terminals of the cell with a wire without an appliance connected in a circuit. This is because by doing so, chemicals in the cell gets used up quickly and after sometime cell will stop working.

 What are the three basic parts of a cell?

physics chemical effects of electric current study about cells electric cell types of cells

  1. Electrodes, electrolyte, container

  2. Electrodes, acid, water

  3. Anode, cathode, ions

  4. Anode, load, depolarize

Show answer
Correct Option: A
Explanation:

A cell is basically a source of energy or electrical energy; there are three basic things required to make a cell work.

$i)$ The source of energy,(electrolyte)
$ii)$ The conduction medium to transfer energy (electrodes)
$iii)$ The contained to stare the energy. 

How many different colors of wire are needed to ignite the bulb when connected with cell ?

physics chemical effects of electric current study about cells electric cell types of cells

  1. 2

  2. 1

  3. 4

  4. 6

Show answer
Correct Option: A
Explanation:

There are two wires needed to connect and ignite the bulb when connected with cell.

$(i)$ To connect the terminal of the cell to the terminal of the bulb.
$(ii)$ The tungsten wire which will get lighten up.
Option $A$ is the correct answer. 

Fill in the blank. 

A _____ is a piece of transparent glass bounded by two spherical surfaces. 

physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

  1. lens

  2. mirror

  3. both  

  4. none 

Show answer
Correct Option: A
Explanation:

A lens is a piece of transparent glass bounded by two spherical surfaces.


Answer is lens.

The focal length of a lens can be expressed in :

physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

  1. metre

  2. dioptre

  3. watt

  4. horse power

Show answer
Correct Option: A
Explanation:

focal length is basically length from the optic centre to the focus, so it is expressed in metres

A straight line passing through the two centres of curvature of lens is called

physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

  1. Normal

  2. Principal axis

  3. Centre axis

  4. Diameter axis

Show answer
Correct Option: B
Explanation:

Principal axis is a straight line passing through the two centres of curvature of lens.

The principal axis is also called _______ of the lens.

physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

  1. optical axis

  2. x-axis

  3. y-axis

  4. axis

Show answer
Correct Option: A
Explanation:

The principal axis is also called optical axis of a lens, passing through the optical center of the lens.

Which of the following term is not associated with a lens ?

physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

  1. Aperture

  2. Focal length

  3. Principal focus

  4. Efficiency

Show answer
Correct Option: D
Explanation:

Aperture of a lens is the length of the surface of lens exposed for incident light.Focal length is the distance between focus of the lens and lens optical center.Principal focus is the focus from which a ray of light traveling parallel to optical axis passes through or appears to pass through after refraction.There is no term like efficiency of a lens.but there is magnification of a lens.

The value of the focal length of the lens is equal to the value of the image distance when the rays are

physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

  1. Passing through the optic centre

  2. Parallel to the principal axis

  3. Passing throught he focus

  4. Over the mirror

Show answer
Correct Option: B
Explanation:

When the object is placed at infinity, i.e., when the rays are parallel to the principal axis, the value of focal length is equal to the value of the image distance.

i.e., object distance , $u=\infty$
From lens formula,

$\dfrac 1f=\dfrac 1u+\dfrac 1v\\\implies \dfrac 1f=\dfrac 1\infty+\dfrac 1v\\\implies f=v$
i.e., image distance is equal to focal length of the lens.