EMF

Q.

Name the two defects in the working of a simple voltaic cell?

Q.

In an electrolytic cell the signs of the cathode and anode are

Q.

Why Electrolytic Cell is non Spontaneous?

Q.

In the transmission of a.c. power through transmission lines, when the voltage is shaped up n times, the power loss in transmission is?

Q.

What is eV (electron-volt) a unit of ? How is it related to its S.I. unit?

1. Force : 1eV = 1.6 x 10^-19 J

2. Power : 1eV = 1.6 x 10^-13 J

3. Force : 1eV = 1.6 x 10^-13 J

4. Energy : 1eV = 1.6 x 10^-19 J

5. Electrical Energy : 1eV = 1.6 x 10^-16 J

Q.

What does $50\mathrm{\mu F}$ mean on a capacitor?

Q. A spring of force constant K is cut into length of ratio 1:2:3 they are connected in series and new force constant K then they are connected in parallel and force constant is k" then the ratio k:k".

Q.

can two equipotential surfaces intersect each other

Q.

What is bench charge?

Q.

A negatively charged body is connected to the ground, then choose the correct statement.

(A) Electrons flow from the body to the ground.

(B) It becomes positively charged.

1. Only A is true.

2. Only B is true

3. Both A and B are true

4. Both A and B are false

Q. The device which can directly measure the electric potential difference between two points is / are:

1. Voltmeter
2. Ammeter
3. Galvanometer
4. Multimeter

Q.

What constitutes an electric current?

Q. spring of force constant k is cut into lengths of ratio 1 : 2 : 3. They are connected in series and the new force constant is k. Then they are connected in parallel and force constant is k. Then k : k is (1) 1 : 6 (2) 1 : 9 (3) 1 : 11 (4) 1 : 14

Q.

Describe Millikans Oil Drop experiment in brief.

Q.

Moving charges constitute

1. electrode

2. electric current

3. static electricity

4. magnetism

Q. How much work is done when one coulomb charge moves against a potential difference of $1Volt$?

Q. Determine the standard emf of the cell and standard free energy change of the cell reaction $Zn|Z{n}^{2+}||N{i}^{2+}|Ni$. The standard reduction potentials of $Z{n}^{2+}|Zn$ and $N{i}^{2+}|Ni$ half cells are $-0.76V$ and $-0.25V$ respectively.

Q. Can the potential difference between the plates of a cell more than its electromotive force (emf)?

Q. Calculate the force on an electric current in a field of1500n/c. Take the charge of an electronic to be 1.6multiplyed by 10to the power6

Q. Given that (at $T=298K)$
$Cu\left(s\right)|C{u}^{2+}\left(1.0M\right)||A{g}^{+}\left(1.0M\right)|Ag\left(s\right)E_{cell}^{\circ }=0.46V$
$Zn\left(s\right)|Z{n}^{2+}\left(1.0M\right)||C{u}^{2+}\left(1.0M\right)|Cu\left(s\right)E_{cell}^{\circ }=1.10V$
The $E_{cell}$ for
$Zn|Z{n}^{2+}\left(0.1M\right)||A{g}^{+}(1.0M|Ag$ at $298K$ will be:

1. $3.56V$
2. $1.53V$
3. $2.53V$
4. Cannot be calculated due to insufficient data

Q. The standard potentials at ${25}^{o}C$ for the following half reactions are given against them as follows:
$Z{n}^{2+}+2e^{-}\to Zn,E^o=-0.762V$
$M{g}^{2+}+2e^{-}\to Mg,E^o=-2.37V$
When zinc dist is added to a solution of magnesium chloride, then:

1. no reaction will take place
2. zinc chloride is formed
3. zinc dissolve in solution
4. magnesium is precipitated

Q. A is a device that sets up a constant potential difference across a conductor in an electric circuit.

1. resistor
2. battery
3. voltmeter
4. generator

Q. State whether true or false :

1. True
2. False

Q. An inductance resistance circuit having a time constant of $50ms$ is connected with an ideal battery of electromotive force $\epsilon$. Find the time elapsed before.
(a) the current reaches half its maximum value,
(b) the power dissipated in heat reaches half its maximum value and
(c) the magnetic field energy stored in the circuit reaches half its maximum value.

Q. Calculate the equilibrium constant for the reaction.
$F{e}^{2+}+C{e}^{4+}|F{e}^{3+}+C{e}^{3+}$, [given: $E^{0}C{e}^{4+}/C{e}^{3+}=1.44$V; $E^{0}F{e}^{3+}/F{e}^{2+}=0.68V]$.

Q. What is electromotive force?

Q. The difference of potential of two electrodes in a galvanic cell is known as:

1. EMF
2. Potential difference
3. Electrode difference
4. Ionic difference

Q. Equipment needed for measuring the potential of a cell:

1. Buret
2. Calorimeter
3. Manometer
4. Geiger counter
5. Voltmeter

Q. Reduction potentials of $A,B,C$ and $D$ are $0.8V,0.79V,0.34V$ and $-2.37V$ respectively. Which element displaces all the other three elements?

1. $A$
2. $B$
3. $D$
4. $C$

Q. if U is equal to zero then we are unable to calculate force is it correct?