List of practice Questions

Two spherical bodies of mass $'m'$ and $5M$ and radii $R$ and $2R$ respectively are released in free space with initial separation between their centres equal to $12\,R$. If they attract each other due to gravitational force only, then the distance covered by the smaller body just before collision is

A strip of copper and another germanium are cooled from room temperature to $80\, K$. The resistance of

Consider telecommunication through optical fibres. Which of the following statements is not true?

In an oscillating LC circuit the maximum charge on the capacitor is The charge on the capacitor when the energy is stored equally between the electric and magnetic field is

A tuning fork of known frequency $256\, Hz$ makes $5$ beats per second with the vibrating string of a piano. The beat frequency decreases to $2$ beats per second when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was

The solubilities of carbonates decrease down the magnesium group due to a decrease in :

Which one of the following processes will produce hard water ?

The substance not likely to contain $CaCO _{3}$ is:

In curing cement plasters water is sprinkled from time to time. This helps in :

In an irreversible process taking place at constant $T$ and $P$ and in which only pressure-volume work is being done, the change in Gibbs free energy (dG) and change in entropy (dS), satisfy the criteria:

The internal energy change when a system goes from state $A$ to $B$ is $40 \,k J / mol$. If the system goes from $A$ to $B$ by a reversible path and returns to state $A$ by an irreversible path, what would be the net change in internal energy?

The de-Broglie wavelength of a tennis ball of mass $60\, g$ moving with a velocity of $10 m / s$ is approximately : (Planck's constant, $h=6.63 \times 10^{-34} \,Js$ )

Several blocks of magnesium are fixed to the bottom of a ship to :

When $U^{238}$ nucleus originally at rest, decays by emitting an alpha particle having a speed u, the recoil speed of the residual nucleus is

A circular disc $X$ of radius $R$ is made from an iron pole of thickness $t$, and another disc Y of radius $4R$ is made from an iron plate of thickness $\frac {t}{4}$. then the relation between the moment of inertia $I_X$ and $I_Y$ is

If the work done in blowing a bubble of volume $V$ is $W$, then the work done in blowing a soap bubble of volume $2\, V$ will be :

A metallic rod of length $l$ is placed normal to the magnetic field $B$ and revolved in a circular path about one of the ends with angular frequency $\omega$. The potential difference across the ends will be :

A magnetic needle suspended in a vertical plane at $30^{\circ}$ from the magnetic meridian makes an angle $45^{\circ}$ with the horizontal. What will be the true angle of dip ?

A force $F$ is given by $F=a t +b t^{2}$, where $t$ is time. What are the dimensions of $a$ and $b$ respectively ?

In hydrogen atom when an electron jumps from second to first orbit, the wavelength of line emitted is :

A rain drop of radius $0.3\, mm$ has a terminal velocity of $1\, m / s$ and the viscosity of $1\, m / s$ and the viscosity of air is $18 \times 10^{-5}$ poise. The viscous force on the drop is:

For a series LCR circuit, the phase difference between current and voltage at the condition of resonance will be :

The wavelength of maximum energy, released during an atomic explosion was $2.93 \times 10^{-10} m$. Given that the Wien's constant is $2.93 \times 10^{-3} m - K$, the maximum temperature attained must be of the order of :

The current gain of a transistor in common emitter mode is $49 .$ The change in collector current and emitter current corresponding to the change in base current by $5.0\, \mu A$ are :

In germanium crystal, the. forbidden energy gap in joule is :