Recent questions tagged 2004

A battery is charged at a potential of 15V for 8 hours when the current flowing is 10A. The battery on discharge supplies a current of 5A for 15 hours. The mean terminal voltage during discharges is 14 V. The "Watt hour" efficiency of the battery is :-

asked Jul 24, 2018 by pady_1

2 answers

One mole of an ideal gas at an initial temperature of T K does 6 R joules of work adiabatically. If the ratio of specific heats of this gas at consta pressure and at constant volume is $\frac {5} {3}$, the final temperature of gas will be :-

asked Jul 24, 2018 by pady_1

2 answers

A coil of 40 henry inductance is connected in series with a resistance of 8 ohm and the combination is joined to the terminals of a 2 volt battery. The time constant of the circuit is :-

asked Jul 24, 2018 by pady_1

1 answer

An electric dipole has the magnitude of its charge as q and its dipole moment is p. It is placed in a uniform electric field E. If its dipol moment is along the direction of the field, the force on it and its potential energy are respectively :-

asked Jul 24, 2018 by pady_1

1 answer

Consider a system of two particles having masses $m_1$ and $m_2$ . If the particle of mass $m_1$ is pushed towards the mass centre of particles through a distance 'd', by what distance would the particle of mass $m_2$ move so as to keep the mass centre of particles at the original position

asked Jul 24, 2018 by pady_1

1 answer

A wheel having moment of inertia $2 kg–m ^{2}$ about its vertical axis, rotates at the rate of 60 rpm about the axis. The torque which can stop the wheel's rotation in one minute would be :-

asked Jul 24, 2018 by pady_1

1 answer

Energy E of a hydrogen atom with principal quantum number n is given by $E=\frac{-13.6} {n^{6}}eV$. n The energy of a photon ejected when the electron jumps from n = 3 state to n = 2 state of hydrogen is approximately :-

asked Jul 24, 2018 by pady_1

1 answer

Three particles, each of mass m gram, are situated at the vertices of an equilateral triangle ABC of side l cm. (as shown in the figure). The moment of inertia of the system about a line AX perpendicular to AB and in the plane of ABC, in gram$\; cm ^2$ units will be :- <br>

asked Jul 24, 2018 by pady_1

1 answer

A block of mass m is placed on a smooth wedge of inclination $\theta$. The whole system is accelerated horizontally so that the block does not slip on th wedge. The force exerted by the wedge on the block (g is acceleration due to gravity) will be :-

asked Jul 24, 2018 by pady_1

1 answer

The ratio of the radii of gyration of a circular disc about a tangential axis in the plane of the disc and of a circular ring of the same radius abou a tangential axis in the plane of the ring is:-

asked Jul 24, 2018 by pady_1

1 answer

If $\lambda_{m}$ denotes the wavelength at which the radioactive emission from a black body at a temperature T K is maximum, then :-

asked Jul 24, 2018 by pady_1

1 answer

The equation of state for 5g of oxygen at a pressure P and temperature T, when occupying a volume V, will be :- <br> Where is the gas constant.

asked Jul 24, 2018 by pady_1

1 answer

A bullet of mass 2 g is having a charge of 2 µC. Through what potential difference must it be accelerated, starting from rest, to acquire a speed of 10 m/s ?

asked Jul 24, 2018 by pady_1

1 answer

The magnetic flux through a circuit of resistance R changes by an amount $\Delta \phi$ in a time $\Delta t$. Then the total quantity of electric charges Q that passes any point in the circuit during the time $\Delta t$ is represented by :-

asked Jul 24, 2018 by pady_1

2 answers

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60W bulb for use in India is R, The resistance of a 60W bulb for use in USA will be :-

asked Jul 24, 2018 by pady_1

1 answer

The dimensions of universal gravitational constant are :-

asked Jul 24, 2018 by pady_1

1 answer

A stone is tied to a string of length 'l' and is whirled in a vertical circle with the other end of the string as the centre. At a certain instant of time, the stone is at its lowest position and has a speed 'u'. The magnitude of the change in velocity as it reaches a position where the string is horizontal (g being acceleration due to gravity) is :-

asked Jul 24, 2018 by pady_1

1 answer

The refractive index of the material of a prism is $\sqrt 2$and its refracting angle is 30º. One of the refracting surfaces of the prism is made a mirror inwards. A beam of monochromatic light entering the prism from the other face will retrace its path after reflection form the mirrored surface if its angle of incidence on the prism is

asked Jul 24, 2018 by pady_1

1 answer

A particle of mass $m_1$ is moving with a velocity $v_1$ and another particle of mass $m_2$ is moving with a velocity $v_2$. Both of them have the same momentum but their different kinetic energies are $E_1$ and $E_2$ respectively. If $m_1$ > $m_2$ then :

asked Jul 24, 2018 by pady_1

1 answer

A beam of light composed of red and green rays is incident obliquely at a point on the face of a rectangular glass slab. When coming out on the opposite parallel face, the red and green rays emerge from :-

asked Jul 24, 2018 by pady_1

2 answers

A galvanometer acting as a voltmeter will have :-

asked Jul 24, 2018 by pady_1

1 answer

The unit of permittivity of free space $\epsilon_0$ is :-

asked Jul 24, 2018 by pady_1

1 answer

Resistances n, each of r ohm, when connected in parallel give an equivalent resistance of R ohm. If these resistances were connected in series, the combination would have a resistance in ohms, equal to

asked Jul 24, 2018 by pady_1

2 answers

The electric resistance of a certain wire of iron i R. If its length and radius are both doubled, then:-

asked Jul 24, 2018 by pady_1

1 answer

When three identical bulbs of 60 watt, 200 volt rating are connected in series to a 200 volt supply, the power drawn by them will be :-

asked Jul 24, 2018 by pady_1

1 answer

The refracting angle of a prism is A and the refractive index of the material of the prism is $\cot (A/2)$. The angle of minimum deviation of the prism is :

asked Nov 20, 2013 by meena.p

1 answer

Assertion (A): Optical fibres are widely used in communication network. Reason (R): Optical fibers are small in size, light weight, flexible and there is no scope for interference in them.

asked Nov 20, 2013 by meena.p

1 answer

Assertion (A): Optical fibres are widely used in communication network. Reason (R): Optical fibers are small in size, light weight, flexible and there is no scope for interference in them.

asked Nov 20, 2013 by meena.p

0 answers

An iron load of 2 kg is suspended in air from the free end of a sonometer wire of length 1 m. A tuning fork is : (Specific gravity of iron=8)

asked Nov 20, 2013 by meena.p

0 answers

The wavelengths of two notes in air are $\large\frac{36}{195}$$m$ and $\large\frac{36}{193}$$m$. Each note produces 10 beats per second separately with a third note of fixed frequency.The velocity of sound in air in m/s is :

asked Nov 20, 2013 by meena.p

1 answer

A black body of mass $34.38\;g$ and surface area$19.2\;cm^2$ is at an initial temperature of $400\;K$. It is allowed to cool inside an evacuated enclosure kept at constant $0.04^{\circ}c$ per second. The specific heat of the body in $J\;kg^{-1} K^{-1}$ is : (Stefan's constant $\sigma = 5.73 \times 10^{-8} Wm ^{-2} K^{-4})$

asked Nov 13, 2013 by meena.p

1 answer

If 4 moles of an ideal monoatomic gas at temperature $400 \;K$ is mixed with 2 moles of another ideal monoatomic gas at temperature $700\;K$ the temperature of the mixture is :

asked Nov 13, 2013 by meena.p

1 answer

The pressure and density of a given mass of a diatomic gas $\bigg(\gamma =\large\frac{7}{5}\bigg)$ change adiabatically from $(P,d)\;to \; (P',d'')$. If $\large\frac{d''}{d}$$=32$, then $\large\frac{P'}{P}$ is $(\gamma$= ratio of specific heats)

asked Nov 13, 2013 by meena.p

1 answer

Two identical vessels A and B with frictionless pistons contains the same ideal gas at the same temperature and the same volume V. The masses of gas in A and B and $m_A$ and $m_B$ respectively. The gases are allowed to expand isothermally to the same final volume 2V. The change in pressures of the gas in A and B are found to be $\Delta P$ and $1.5 \Delta\;P$respectively. Then:

asked Nov 13, 2013 by meena.p

1 answer

A metallic solid sphere is rotating about its diameter as axis of rotation . If the temperature is increased by $200^{\circ}C$, the percentage increase in its moment of inertia is : (Coefficient of linear expansion of the metal $=10^{-5/^{\circ}C}$)

asked Nov 13, 2013 by meena.p

1 answer

There are two holes one each along the opposite sides of a wide rectangular tank. The cross- section of each hole is $0.01m^2$ and the vertical distance between the holes is one meter. The tank is filled with water the net force on the tank in newton when the water flows out of the holes is : (Density of water $=1000\;kg/m^3)$

asked Nov 13, 2013 by meena.p

1 answer

Water in a river 20 m deep is flowing at a speed of $10\;ms^{-1}$. The shearing stress between the horizontal layers of water in the river in $Nm^{-2}$ is : (Coefficient of viscosity of water $=10^{-3}SI$ units)

asked Nov 13, 2013 by meena.p

0 answers

One end of a uniform glass capillary tube of radius $r=0.025\;cm$ is immersed vertically in water to a depth $h=1\;cm$. The excess pressure in $N/m^2$ required to blow an air bubble out of the tube: (Surface tension of water$= 7 \times 10^{-2} N/m$ Density of water$= 10^3 kg/m^3$ Acceleration due to gravity $=10 m/s^2$)

asked Nov 13, 2013 by meena.p

1 answer

One end of a uniform glass capillary tube of radius $r=0.025\;cm$ is immersed vertically in water to a depth $h=1\;cm$. The excess pressure in $N/m^2$ required to blow an air bubble out of the tube: (Surface tension of water$= 7 \times 10^{-2} N/m$ Density of water$= 10^3 kg/m^3$ Acceleration due to gravity $=10 m/s^2$)

asked Nov 13, 2013 by meena.p

0 answers

A metalic ring of radius r and cross sectional area A is fitted into a wooden circular disc of radius $R(R > 1)$. If the Young's modulus of the material of the ring is Y, the force with which the metal ring expands is :

asked Nov 13, 2013 by meena.p

1 answer

The time period of a simple pendulum is T. When the length is increased by 10 cm,its period is $T_1$. When the length is decreased by 10 cm, its period is $T_2$. Then, the relation between $T,T_1\;and T_2$ is :

asked Nov 13, 2013 by meena.p

1 answer

The escape velocity of a body on the earth's surface is $v_e$. A body is thrown up with a speed $\sqrt 5 v_c$. Assuming that the sun and planets do not influence the motion of the body, velocity of the body at infinite distance, is :

asked Nov 13, 2013 by meena.p

1 answer

A particle of mass 1 kg is projected with an initial velocity $10\;ms^{-1}$ at an angle of projection $45^{\circ}$ with the horizontal. The average torque acting on the projectile, between the time at which it is projected and the time at which it strikes the ground, about the point of projection in newton-meter is :

asked Nov 13, 2013 by meena.p

1 answer

A thin uniform square lamina of side a is placed in the xy-plane with its sides parallel to x and y-axes and with its center coinciding with origin. Its moment of inertia about an axis passing through a point on the y-axis at a distance $y=2a$ and parallel to x-axis is equal to its moment of inertia about an axis passing through a point on the x-axis at a distance $x=d$ and perpendicular to xy-plane. Then value of d is :

asked Nov 13, 2013 by meena.p

1 answer

Consider the following statements A and B and identify the correct answer:A : When a person walks on a rough surface the direction of frictional force exerted by the surface on the person is opposite to the direction of his motion. B : When a cycle is in motion, the force of friction exerted by the ground on the front wheel is in the backward direction:

asked Nov 13, 2013 by meena.p

1 answer

Two particles of equal mass have velocities $\overrightarrow {v_1}=4 \hat i$ and $\overrightarrow{v_2} =4 \hat j ms^{-1}$. First particle has an acceleration $\overrightarrow{a_1}=(5 \hat i+5 \hat j)ms^{-2}$ while the accleration of the other particle is zero. The center of mass of the two particles moves in a path of :

asked Nov 13, 2013 by meena.p

1 answer

The block of mass 2 kg is initially at rest on a horizontal force $\overrightarrow {F}=(9-x^2) \hat i$ newtons acts on it, when the block is at $x=0$. The maximum kinetic energy of the block between $x=0$ and $x=3m$ in joule is :

asked Nov 13, 2013 by meena.p

1 answer

A 2 kg ball moving at $24 ms^{-1}$ undergoes inelastic head-on collision with a 4 kg ball moving in the opposite direction at $48\;ms^{-1}$. If the coefficient of restitution is $2/3$, their velocities in $ms^{-1}$ after impact are :

asked Nov 13, 2013 by meena.p

1 answer

The horizontal and vertical displacements x and y of a projectile at a given time t are given by $x=6t$ meter and $y=8 t -5t^2$ metre. The range of the projectile in meter is :

asked Nov 13, 2013 by meena.p

1 answer

At a given instant of time two particles are having the position vectors $4 \hat i+4 \hat j+57 \hat k$ metres and $2 \hat i+2 \hat j+5 \hat k$ respectively. If the velocity of the first particle be $0.4 \hat i ms^{-1},$ the velocity of second particle in meter per second if they collide after 10 sec is :

asked Nov 13, 2013 by meena.p

1 answer

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