Current electricity practice · Mixed difficulty

Electroplating does not help in

When an unknown resistance and a resistance $6 \,{\Omega}$ are connected in the left and right gaps of a meter bridge, the balance point is obtained at $50 {~cm}$. If $3\, \Omega$ resistance is connected in parallel to resistance in right gap, the balance point is

When $\mathrm{1 }\,\mathrm{A}$ current flows for $\mathrm{1}\,\,\mathrm{min}$ through a silver voltmeter, it deposits $\mathrm{0}\mathrm{.067}\,\,\mathrm{g}$ of silver on the cathode, then how much charge will flow to deposit $\mathrm{108}\,\,\mathrm{g}$ of silver?

Peltier coefficient for the junction of a pair of metals is proportional to

For which of the following dependence of drift velocity $\mathrm{v_d}$ on electric field $\mathrm{E}$, is Ohm's law obeyed?

Assertion: Total current entering a circuit is equal to that leaving it by Kirchhoff's law.
Reason: It is based on conservation of energy.

When a current of $\mathrm{1}\,\,\mathrm{ampere}$ is passed through a conductor whose ends are maintained at temperature difference of $1\,{\,^0}\mathrm{C}$, the amount of heat evolved or absorbed is called

A fuse wire of circuit cross-section and having diameter of $\mathrm{0}\mathrm{.4}\,\,\mathrm{mm}$, allows $\mathrm{3}\,\,\mathrm{A}$ of current to pass through it. But if another fuse wire of same material and circular cross-section and having diameter of $\mathrm{0}\mathrm{.6}\,\,\mathrm{mm}$ is taken, then the amount of current passed through the fuse is

In a thermocouple, the temperature that does not depend on the temperature of the cold junction is called

According to Joule’s law, if the potential difference across a conductor having a material of specific resistance remains constant, then the heat produced in the conductor is directly proportional to

The thermocouple among the following that can produce maximum thermo-emf for the same temperature difference between the junction is

If an electric current is passed through a nerve of a man, then man

Which of the following statements is false?

The electron in a hydrogen atom circles around the proton in $1.5941\,\, \times \,\,{10^{ - 18}}$. The equivalent current due to motion of the electrons is

$Ohm's$ law is true

For a given thermocouple neutral temperature

$Watt - hour$ meter measures

In "$Al$" and "$Si$". If temperature is changed from normal temperature to $70 \mathrm{~K}$ then

An immersion heater with electrical resistance $7\,\,\mathrm{\Omega }$ is immersed in $\mathrm{0}\mathrm{.1}\,\,\mathrm{kg}$ of water at $20\,{\,^0}\mathrm{C}$ for $\mathrm{3}\,\,\mathrm{min}$. If the flow of current is $\mathrm{4}\,\,\mathrm{A}$, what is the final temperature of the water in ideal conditions? ${\left( {\mathrm{Specific heat }\,\mathrm{capacity}\,\mathrm{ of }\,\mathrm{water} = 4.2\,\, \times \,{{10}^3}\,\,\mathrm{Jkg}} \right)^{ - 1}}{\mathrm{K}^{ - 1}}$

In a meter bridge, null point is $20 \mathrm{~cm}$. When the known resistance $\mathrm{R}$ is shunted by $10 \Omega$ resistance, null point is found to be shifted by $10 \mathrm{~cm}$. The value of unknown resistance $\mathrm{X}$ is.

When a current passes through the junction of two different metals, evolution or absorption of heat at the junction is known as

One junction of thermocouple is at $0\,{\,^0}\mathrm{C}$ and the other is at $T\,{\,^0}\mathrm{C}$. The thermo emf (in volts) is given by $E = 20\,\, \times \,\,{10^{ - 6}}\,\,T - 0.02\,\, \times \,\,{10^{ - 6}}\,\,{T^2}$ The maximum value of $E$ is

A capacitor of capacity $C$ is charged to a potential difference $V$ and another capacitor of capacity $2 \mathrm{C}$ is charged to a potential difference $4 \mathrm{~V}$. The charging batteries are disconnected and the two capacitors are connected with reverse polarity (i.e. positive plate of first capacitor is connected to negative plate of second capacitor). The heat produced during the redistribution of charge between the capacitors will be

For comparing the e.m.f.'s of two cells with a potentiometer, a standard cell is used to develop a potential gradient along the wires. Which of the following possibilities would make the experiment unsuccessful

If in a voltaic cell, $\mathrm{5}\,\,\mathrm{g}$ of zinc is consumed, we will get how many ampere hour (given that $\mathrm{ECE}$ of zinc is $3.38\,\, \times \,\,{10^{ - 7}}\,\,\mathrm{kg}{\mathrm{C}^{ - 1}}$)

Three unequal resistors in parallel are equivalent to a resistance $1\,\,\mathrm{\Omega }$. If two of them are in the ratio $\mathrm{1:2}$ and if no resistance value is fractional, the largest of the three resistance in ohm is

Under what condition will the strength of current in a wire of resistance $R$ be the same for connection is n series or in parallel of $n$ identical cells each of the internal resistance $r$, when

A current passes through a wire of unequal cross-sectional area. The one that does not depend on cross- section among the following is

As the temperature rises the resistance offered by metals

Two identical cells send the same current in $3\,\,\Omega$resistance, whether connected in series or in parallel. The internal resistance on the cell should be