List of practice Questions

At time $t = 0$, activity of radioactive substance is $1600 \,Bq$, at $t = 8 \,s$ activity falls to $100 \,Bq$. The activity at $t = 2\, s$ is
An echo repeats four syllables. The distance of the reflecting surface, if it takes one-fifth of a second to pronounce or hear one syllable distinctly is (Velocity of sound $= 340\,ms^{-1}$)
In a transistor amplifier, $\beta = 62$, $R_L = 5000\,\Omega$ and input resistance of the transistor is $500\, \Omega$. What is power amplification ?
A thin equiconvex lens of refractive index $\frac{3}{2}$ and radius of curvature $30\, cm$ is put in water (refractive index = $\frac{4}{3})$, its focal length is
A stationary object at $ 4{}^\circ C $ and weighing 3.5 kg falls from a height 2000 m on a snow mountain at $ 0{}^\circ C $ . If the temperature of the object just before hitting the snow is $ 0{}^\circ C $ and the object before comes to rest immediately $ (g=10\text{ }m/{{s}^{2}}) $ and latent heat of ice $ =3.5\times {{10}^{5}} $ J/s), then the object
A spring balance $A$ and a beam balance $B$ are used to weigh the same object at a place on the equator and a place on the pole of the earth. Then
A spherical solid ball of volume $V$ is made of a material of density $\rho_1$ It is falling through a liquid of density $\rho_2(\rho_2 < \rho_1)$. Assume that the liquid applies a viscous force on the ball that is $F = krv$ where $r$ is the radius of the ball and $v$ is the speed and $k$ is the constant of proportionality. The terminal speed of the ball is
"A spherically symmetric gravitational system of particles has a mass density $\rho =\Biggl \{ \begin{array} \ \rho_0 \ \text{for} \ r \le R\\ 0 \ \text{for} r\ > \ R \\ \end{array}$ , where $\rho _0$ is a constant. A test mass can undergo circular motion under the influence of the gravitational field of particles. Its speed v as a function of distance r from the centre of the system is represented by"
A spontaneous reaction is impossible if
Tissue level of organisation is not found in
$A$ and $B$ antigens are not found in which of the following blood group?
A satellite revolves round the earth. Air pressure inside the satellite is maintained at $76 \,cm$ of mercury. What will be height of mercury column in a barometer tube $100\, cm$ long placed in the satellite?
A rigid bar of mass $M$ is supported symmetrically by three wires each of length $L$. Those at each end are of copper and the middle one is of iron. The ratio of their diameters, if each is to have the same tension, is equal to
If $13 e^{i \, \tan^-1} \frac{5}{12}} = a + ib $, then the ordered pair $(a , b) = $
Two point charges $+2C$ and $+ 6C$ repel each other with a force of $12 \,N$. If a charge of $- 2C$ is given to each of these charges the force will now be
A metal oxide has the formula $ A_{2}O_{3}$ . It can be reduced by hydrogen to give free metal and water. $0.1596\, g$ of this metal oxide requires $6\, mg$ of hydrogen for complete reduction. What is the atomic weight of metal?
In the $ABO$ system of blood groups, if both antigens are present but no antibody, the blood group of the individual would be
A box whose mass is $5\, kg$ lies on a spring balance inside a lift. The lift starts to ascend with an acceleration of $2\, ms ^{-2}$. The reading of the machine or balance is $\left(g=10\, ms ^{-2}\right)$
The major product of the reaction of with electrophile, $ E^{+} $ , is
Which one of the following is an example of $ 3^{\circ} $ amide?
If $A =(5,3) , B = (3, -2)$ and a point $P$ is such that the area of the triangle $PAB$ is $9$, then the locus of $P$ represents
Which of the following is the most dangerous metal pollutant of automobile exhaust ?
Which of the following species is not electrophilic in nature ?
Which one is not a pollutant normally?
Which one of the following is a chain growth polymer ?