Recent questions in Physics

An object of length 3 cm is placed on the principle axis of a concave mirror of focal length f at a distance of 4f. The length of the image will be :

asked Jan 16, 2014 by meena.p

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A concave mirror of focal length f(in air) is immerssed in water $(\mu =\large\frac{4}{3} ) $. The focal length of mirror in water will be

asked Jan 15, 2014 by meena.p

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Which one of the following statement is true.

asked Jan 15, 2014 by meena.p

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Two plane mirrors are inclined to each other at some angle. A ray of light incident at $30^{\circ}$ on one mirror after reflection from the other mirror retracts its path. The angle between the mirror is :

asked Jan 15, 2014 by meena.p

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A ray of light is reflected by two plane mirror mutually at right angles to each other. What is the deviation of reflected ray from the incident ray

asked Jan 15, 2014 by meena.p

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A ray of light is incident at an angle of $20^{\circ}$ to the normal. What is the deviation caused due to reflection?

asked Jan 15, 2014 by meena.p

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A man is walking towards the plane mirror at the speed of $4 km/hr$ . What is the speed with which he is approaching his image?

asked Jan 15, 2014 by meena.p

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Two plane mirrors are inclined to each other in such a way that a ray of light moving parallel to one mirror comes out parallel to the other mirror after two reflections. The angle between the mirrors is :

asked Jan 15, 2014 by meena.p

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A ray of light is incident at $30^{\circ} $ on the plane mirror. What is the angle between mirror and reflected ray ?

asked Jan 15, 2014 by meena.p

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Given electric field $ \overrightarrow {E} =[1 \times (d + x) \hat i +E_0 \hat j ] N/c$. If a closed surface as shown below is considered , find the change enclosed.

asked Jan 15, 2014 by meena.p

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Two point particles of same mass M are attached to two ends of a massless non-conducting rigid rod of length l. The charge on particle are +q and -q. The rod is held in a region of uniform electric field E making an angle $\theta $( very small) with E. The time t , after itself parallel to electric field after releasing it is :

asked Jan 15, 2014 by meena.p

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Two point particles of same mass M are attached to two ends of a massless non-conducting rigid rod of length l. The charge on particle are +q and -q. The rod is held in a region of uniform electric field E making an angle $\theta $( very small) with E. When rod is released , its angular frequency will be :

asked Jan 15, 2014 by meena.p

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Two point particles of same mass M are attached to two ends of a massless non-conducting rigid rod of length l. The charge on particle are +q and -q. The rod is held in a region of uniform electric field E making an angle $\theta $( very small) with E. Magnitude of torgue on rod will be equal to:

asked Jan 15, 2014 by meena.p

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Three infinite long plane sheets carrying charge densities $\sigma _1 =+3 \sigma , \sigma _2 =+2 \sigma $ and $\sigma _3 =- \sigma $ are placed parallel to $x-z$ plane at $y=4a,y=3a$ and $y=a $ respectively. Electric field at point P is :

asked Jan 15, 2014 by meena.p

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A charge $-q$ is fixed at each of the points $x= 2 m,x=4m,x=6m.... $ up to infinity and charge $+q$ is fixed at each of the points $x=1 m ,x= 3m , x=5m....$ up to infinity. The potential at the origin will be :

asked Jan 15, 2014 by meena.p

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If electron of mass $m_e$ moves through a certain distance in a uniform electric field in time $t_1$ and proton of mass $m_p$ moves same distance in time $t_2$ , the ratio $\large\frac{t_1}{t_2}$ will be :

asked Jan 15, 2014 by meena.p

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The force of attraction between the plates of parallel plate capacitor having area A and charge Q is given by

asked Jan 15, 2014 by meena.p

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A capacitor of capacitance $C_0$ is charge to potential $V_0$ and then isolated . A small capacitor C is charged from $C_0$, discharge and then charged again; this process is repeated n times. Due to this potential of $C_0$ decreases to r. Value of C is :

asked Jan 15, 2014 by meena.p

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If electric field $\overrightarrow{E} = 2\hat i +3 \hat j $ , Potential difference between two point $V_A- V_B$, where $r_A=\hat i+ 2 \hat j $ and $r_B=2 \hat i +\hat j + 3 \hat k $ will be

asked Jan 15, 2014 by meena.p

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Two thin rings of radius R are placed at a distance a between them such that their axes coincide. Potential difference between the centre of the ring will be , if charges on rings are $+q $ and $-q$

asked Jan 13, 2014 by meena.p

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A spherical shell of radius R has a charge Q uniformly distributed on its surface. What is the force exerted by one half over the other.

asked Jan 13, 2014 by meena.p

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Find electric field at point $(a,a,a) $ due to three infinitely long lines of charge density $\lambda$ along $x,y $ and $ z$ axis

asked Jan 13, 2014 by meena.p

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Three identical spheres , each having a charge q and radius R are kept in such a way that each touches the other two. Find magnitude of electric force on any sphere due to other two sphere,

asked Jan 13, 2014 by meena.p

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What will be the electric field at point P. Assume (r >> a)

asked Jan 13, 2014 by meena.p

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The capacitor plates are fixed on inclined plane p connected to a battery of emf E. A dielectric slab of mass m and dielectric constant k is inserted into the capacitor and tied to mass M using a weightless string as shown. If capacitance have plate area A, length l and distance d between them. Find M such that slab stays in equilibrium. Assume zero friction between slab and plates

asked Jan 13, 2014 by meena.p

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A ring of radius R carries charge $+q$ uniformly distributed on it. If a charge $- 90$ is released on ring's axis at a distance $\sqrt 3 R$ from its centre , the kinetic energy of $-90$ when it reaches the centre of ring will be :

asked Jan 13, 2014 by meena.p

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Six plates of same area A are arranged as shown. Equivalent capacitance of arrangement between A and B is :

asked Jan 13, 2014 by meena.p

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A uniform electric field of $200 \;Vm^{-1} $ is directed $60^{\circ}$ to $+ve$ X-axis . If $OA=2 m, V_0-V_A$ is

asked Jan 13, 2014 by meena.p

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Three concentric spherical conductors are shown, Find equivalent capacitance b/w A and B

asked Jan 13, 2014 by meena.p

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A parallel plate capacitor is immersed in liquid of dielectric constant K. Find force per unit area acting on plate from the liquid from dielectric in contact with the plate.

asked Jan 13, 2014 by meena.p

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A cylindrical layer of homogeneous dielectric with dielectric constant K is introduced in a cylindrical capacitor so that a gap of width d is filled in between them. Radius of plate $R > > d$. If the capacitor is connected to battery of EMF V, the force pulling the dielectric inside the capacitor is :

asked Jan 13, 2014 by meena.p

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A point charge Q is placed at the centre of an imaginary Gaussian surface. Find flux through curved surface.

asked Jan 13, 2014 by meena.p

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Electric field intensity due to a semi- infinite wire at a point A as shown is :

asked Jan 13, 2014 by meena.p

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In the circuit given below, the position of switch S is shifted from 1 to 2 . choose the correct statement

asked Jan 10, 2014 by meena.p

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A thin metal sheet is placed between the plates of a parallel plate capacitor. Its capacitance will

asked Jan 10, 2014 by meena.p

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Potential difference between points A and B is 5V, then voltage across $2 \mu F$ capacitor is :

asked Jan 10, 2014 by meena.p

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Three identical metal plates are kept parallel to one another at seperation $d_1\; and\; d_2 $ If both the outer plates are connected to ground and middle plate is given charge q, The charge on right side of middle plate will be :

asked Jan 10, 2014 by meena.p

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A charged particle moves in a circle around an infinite line charge such that center of circle lies on line and line is perpendicular to plane of circle. If r is the radius of circle the velocity of particle will depend on which power of r .

asked Jan 10, 2014 by meena.p

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A conducting spherical shell is earthed. A +ve charge $+q_1$ is placed at its centre and another +ve charge $+q_2$ is placed outside at a distance d from centre . If the conducting spherical shell is not earthed , then force on $q_2$ is:

asked Jan 10, 2014 by meena.p

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A conducting spherical shell is earthed. A +ve charge $+q_1$ is placed at its centre and another +ve charge $+q_2$ is placed outside at a distance d from centre . If the effect of induced charge due to $q_2$ on sphere is ignored. Then coulomb force on $q_2$

asked Jan 10, 2014 by meena.p

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A charge particle of mass 1 kg and charge $ 1 \mu c$ is projected from horizontal ground at an angle $ \theta=45^{\circ}$ with speed $10 ms^{-1}$. In space a horizontal electric field towards the direction of projection $E= 10^{7}NC^{-1}$ exists. The range of projectile is :

asked Jan 10, 2014 by meena.p

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A charge Q is placed at a distance $D( > R)$ above the centre of disk of radius R The magnitude of flux through disk is $\phi$ . Now a hemispherical shell of radius R is put above the disk to form a closed surface. The flux through the closed surface, if direction of area vector along outward normal is +ve, is :

asked Jan 10, 2014 by meena.p

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Two infinite long parallel wires having linear charge densities $\lambda_1\; and\; \lambda_2 $ respectively are placed at a distance R. The force per unit length on wire (1) will be:

asked Jan 10, 2014 by meena.p

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Find the equivalent capacitance between A ans B ,each capacitor having capacitance C.

asked Jan 10, 2014 by meena.p

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If a dielectric slab is inserted in between a capacitor of capacitance C after charging it to a potential V, the net charge on surfaces shown below will be :

asked Jan 10, 2014 by meena.p

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If a point charge is placed at the centre of closed cylindrical conductor of length l and radius R. the flux through the cylinder will be :

asked Jan 9, 2014 by meena.p

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A circular ring of radius R has charge Q distributed uniformly on it. If a space of radius R, has its centre lying on boundary of the ring, then flux coming out of sphere will be :

asked Jan 9, 2014 by meena.p

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An infinite long semicircular tube is given as shown below one half is given a surface charge density $+\sigma$ and other half is given charge density $-,\sigma $ . Electric field at a point on axis would be

asked Jan 9, 2014 by meena.p

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Mark the correct statements :

asked Jan 9, 2014 by meena.p

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The correct statement for the phenomenon of "Electrostatic Induction " is :

asked Jan 9, 2014 by meena.p

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