AIEEE 2003 (Physics) Mock Test

The thermo e.m.f. of a thermo-couple is $25\mu {\text{V/}}^{\circ }\text{C}$ at room temperature. A galvanometer of $40\Omega$ resistance, capable of detecting current as low as $10^{-5}\text{A}$, is connected with the thermocouple. The smallest temperature difference that can be detected by this system is:

The negative $\text{Zn}$ pole of a Daniell cell, sending a constant current through a circuit, decreases in mass by $0.13\text{g}$ in $30\text{minutes}$. If the electrochemical equivalent of $\text{Zn}$ and $\text{Cu}$ are $32.5$ and $31.5$ (arbitrary units or mass ratio) respectively, the increase in the mass of the positive $\text{Cu}$ pole in this time is:

Dimensions of $\frac{1}{{\mu }_0{ϵ}_0}$, where symbols have their usual meaning, are:

A circular disc $X$ of radius $R$ is made from an iron plate of thickness $t$, and another disc $Y$ of radius $4R$ is made from an iron plate of thickness $t/4$. The relation between the moment of inertia $I_X$ and $I_Y$ is:

The time period of a satellite of earth is $5\text{hours}$. If the separation between the earth and the satellite is increased to $4$ times the previous value, the new time period will become: