Tag: physics

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Questions Related to physics

Multiple choice types of cells electricity physics

Primary cell are connected in parallel to

  1. Increase voltage

  2. Decrease capacity

  3. Decrease internal resistance

  4. Make electric current constant
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Equivalent resistance of parallel combination         $\dfrac{1}{R _{eq}}  = \dfrac{1}{R _1}+\dfrac{1}{R _2} + .......$


$\implies$ Equivalent resistance of the parallel combination is less than the minimum of the individual resistance used.

Hence primary cell are connected in parallel to decrease the internal resistance.

Multiple choice types of cells electricity physics

What is the e.m.f. of a dry cell ?

  1. $1.5 V$
  2. $2.5 V$
  3. $1.1 V$
  4. $-1.1 V$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A common dry cell is the zinc–carbon battery, sometimes called the dry Leclanché cell, with a nominal voltage of 1.5 volts, the same as the alkaline battery (since both use the same zinc–manganese dioxide combination).Hence the correct option A.
Multiple choice types of cells electricity physics

The depolariser used in Laclanche cell is

  1. Solution of ammonium chloride

  2. Porous pot

  3. Powdered carbon

  4. Manganese dioxide
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A battery depolarizer takes up electrons during discharge of the cell and thus it is always an oxidizing agent. The term depolarizer has been used to denote a substance used in primary cell to prevent build up of hydrogen gas bubbles. Manganese dioxide is used as depolarizer in Leclanche cell and dry cell.

Multiple choice types of cells electricity physics

When the two terminals of a battery are connected directly with a wire then:

  1. more electrical energy is stored in the cell

  2. the chemical energy stored get used up very fast.

  3. no current flows in the wirc

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

Battery is the source of potential difference and wire is a conductor but can't be a perfect conductor. It has some resistance in which voltage gets dropped. As resistance of wire is much smaller so it will be large amount of current through battery and battery will get discharged much sooner.the chemical energy stored get used up very fast.

Multiple choice types of cells electricity physics

Electro chemical equivalent of substance is 0.0006735 ; its eq. wt. is :

  1. 65

  2. 67.35

  3. 130

  4. cannot be calculated
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The electrochemical equivalent (Z) is related to equivalent weight (E) by the formula Z = E / F, where F is Faraday's constant (approximately 96500 C/mol). E = Z * F = 0.0006735 * 96500 = 64.99, which rounds to 65.

Multiple choice types of cells electricity physics

In a cell, electrons move from

  1. positive electrode to negative electrode.

  2. negative electrode to positive electrode.

  3. both A and B

  4. electrons do not move and only negative charge moves from one place to another place.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We know that the current flows from positive electrode to negative electrode in a cell. The direction of electrons is always opposite to the direction of the current. Thus, the electrons move from negative electrode to positive electrode.  

Multiple choice types of cells electricity physics

Which one of the following statement is not true for Daniel cell ?

  1. The e.m.f. of this cell changes rapidly

  2. Some crystals of copper sulphate are added in it to make the solution saturated

  3. This cell was made first of all in 1850 by the scientist Daniel

  4. The hollow cylinder or the vessel of copper acts as the positive plate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The e.m.f of a Daniel cell always remains constant and is equal to $1.08$ volts.

And  all the other statements given are true.

Multiple choice types of cells electricity physics

Direction of electric current inside the cell is from

  1. positive electrode to negative electrode.

  2. negative electrode to positive electrode.

  3. positive electrode to positive electrode.

  4. negative electrode to negative electrode.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When an external circuit is connected across the cell, electrons flow from negative electrode to positive electrode(current flows opposite to this) in the external circuit. Inside the cell, negatively charged ions are attracted to negative electrode because it is depleted of electrons. Similarly, inside the cell, positively charged ions are attracted to positive electrode. 

Hence inside the cell, current flows from negative electrode to positive electrode.

Multiple choice types of cells electricity physics

The common dry cell produces a voltage of

  1. $1.5 V$
  2. $4 V$
  3. $2 V$
  4. $3 V$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A common dry cell is zinc-carbon cell with a normal voltage of 1.5 V , same as the alkaline cell.

Multiple choice types of cells electricity physics

A battery converts chemical energy into

  1. mechanical energy

  2. solar energy

  3. electrical energy

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

A battery converts chemical energy into electrical energy.


Answer-(C)