List of practice Questions

During the electrolysis of molten sodium chloride, the time required to produce $0.10$ mol of chlorine gas using a current of $3$ amperes is

Cotyledon of maize grain is called :

Consider the reaction ${ CH3CH2CH2Br + NaCN -> CH3CH2CH2CN + NaBr } $ This reaction will be the fastest in

Consider the nitration of benzene using mixed conc. $ {H_2SO_4}$ and ${HNO_3}$. If a large amount of ${KHSO_4}$ is added to the mixture, the rate of nitration will be :

Conifers are adapted to tolerate extreme environmental conditions because of -

Coefficient of linear expansion of brass and steel rods are $\alpha_1$ and $\alpha_2$. Lengths of brass and steel rods are $ l_1$ and $l_2$ respectively. If $(l_2 - l_1)$ is maintained same at all temperatures, which one of the following relations holds good ?

At what height from the surface of earth the gravitation potential and the value of g are $- 5.4 \times 10^7 \, J \, kg^{-2}$ and $6.0 \, ms^{-2}$ respectively ? Take the radius of earth as $6400 \,km$ :

Blood pressure in the pulmonary artery is

Asthma may be attributed to :

Antivenom injection contains preformed antibodies while polio drops that are administered into the body contain -

An inductor $20\, mH$, a capacitor $50\, \mu F$ and a resistor $40 \, \Omega $ are connected in series across a source of emf $V = 10 \, \sin \, 340\,t$. The power loss in A.C. circuit is :

An electron is moving in a circular path under the influence of a transverse magnetic field of $3.57 \times 10^{-2} T$. If the value of $e / m$ is $1.76 \times 10^{11} C / kg$, the frequency of revolution of the electron is

An astronomical telescope has objective and eyepiece of focal lengths $40\, cm$ and $4 \,cm$ respectively. To view an object $200\, cm$ away from the objective, the lenses must be separated by a distance :

An air column, closed at one end and open at the other, resonates with a tuning fork when the smallest length of the column is $50\,cm$. The next larger length of the column resonating with the same tuning fork is :

An air bubble in a glass slab with refractive index $1.5$ (near normal incidence) is $5\,cm$ deep when viewed from one surface and $3\,cm$ deep when viewed from the opposite face. The thickness (in cm) of the slab is

Among the following, which one is a wrong statement?

Among the following the correct order of acidity is :

A uniform magnetic field is restricted within a region of radius $r$. The magnetic field changes with time at a rate $\frac{d \vec{B}}{dt}$. Loop $1$ of radius $R > r$ enclosed the region $r$ and loop $2$ of radius $R$ is outside the region of magnetic field as shown in the figure below. Then the e.m.f. generated is

A uniform circular disc of radius 50 cm at rest is free to turn about an axis which is perpendicular to its plane and passes through its centre. It is subjected to a torque which produces a constant angular acceleration of $2.0 \, rad \, s^{-2}$. Its net acceleration in $ms^{-2}$ at the end of 2.0 s is approximately :

A true breeding plant is -

A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed the resulting genotypes were in the ratio of -

A system of rotating crops with legume or grass pasture to improve soil structure and fertility is called :

A siren emitting a sound of frequency $800\, Hz$ moves away from an observer towards a cliff at a speed of $15\,m\,s^{-1}$. Then, the frequency of sound that the observer hears in the echo reflected from the cliff is : (Take velocity of sound in air = $330 \, ms^{-1}$)

A refrigerator works between $4^{\circ}C$ and $30^{\circ}C$. It is required to remove $600\, calories$ of heat every second in order to keep the temperature of the refrigerated space constant. The power required is : $(Take\, 1 \,cal\, =\, 4.2 \,Joules)$

A piece of ice falls from a height h so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h is : [Latent heat of ice is $3.4 \times 10^5 \, J/kg$ and $g = 10 \, N/kg$]