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An electric charge `q` is placed at one of the corners of a cube of side `a`. The electric flux on one of its faces will

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: When charges are shared between any two bodies, then no charge is really lost but some loss of energy does occur. Reason: Some energy disappears in the form of heat, sparking,

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Charge between Parallel Plates Surface charge density is defined as the charge per unit surface area of surface charge distribution, `i.e. sigma = (dq)/(dS)`Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs having magnitude of `17.0 xx 10^(-22) Cm^(-2)` as shown belowThe intensity of electric field at a point is `E=(sigma)/(epsilon_0)`where, `epsilon_0` = permittivity of free spaceIn order to estimate the electric field due to a thin finite plane metal plate, the gaussian surface considered

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Assertion: A potentiometer is preferred over a voltmeter for measurement of a cell. Reason: Potentiometer does not draw any current from the

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Lorentz Force and Its Effects A charged particle moving in an external magnetic field experiences a force, which is called Lorentz force, i.e. `F=q(v xx B)`,where `q` is the charge on the particle and v is the velocity of the particle. The direction of the force is given by the cross product of velocity vector and magnetic field vector at any time.The charge particle travels in a special trajectory called helical path. Because the force is always perpendicular to the velocity vector, the magnetic field can do no work on an isolate charge. Hence, the linear velocity always remains the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: According to Gauss’s law for magnetism, the net magnetic flux through any closed surface is zero. Reason: The number of magnetic field lines leaving the surface is balanced by the number of lines entering

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Gauss Law in Magnetism We can write Gauss’s law for magnetostatics as `intB.dA=mu_0m`, where, `intB •dA`. is the magnetic flux and m is the net magnetic pole strength inside a closed surface. It was found that, magnetic flux through a closed surface is always zero, thus we reach at a conclusion that magnetic monopoles do not exist. A bar magnet always attain north-south poles no matter how many times it is cut into pieces.The number of magnetic field lines passing through a surface area normally is

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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L-C Oscillations When a capacitor is supplied with an AC circuit, it gets charged.When this charged capacitor is connected with an inductor, current flows through inductor, giving rise to magnetic flux. Hence, induced emf is produced in the circuit. Due to this, the charge on the capacitor decreases and an equivalent amount of energy is stored in the inductor in the form of magnetic Field.The physical quantity that has same dimension as that of `sqrt(LC)`

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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AC Generator An AC generator produces electrical energy from mechanical work, just the opposite of what a motor does. In it, a shaft is rotated by some mechanical means, such as an engine or a turbine starts working and an emf is induced in the coil.It is based on the phenomenon of electromagnetic induction which states that whenever magnetic flux linked with a conductor (or coil) changes, an emf is induced in the coil. An AC generator consists of a coil of 1000 turns and cross-sectional area of `100 cm^2`, rotating at an angular speed of 100 rpm in a

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The Transformer Transformer is a device, which is used to increase or decrease the alternating voltage. The transformers are of the following types (i) Step-up transformer (ii) Step-down transformerTransformer is based upon the principle of mutual induction. It consists of two coils, primary coil `(p)` and secondary coil `(s)`, insulated from each other wounded on soft iron core.Often the primary coil is the input coil and secondary coil is the output coil. These soft iron cores are laminated to minimise eddy current loss.What is not possible in a

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Double-convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of the same radius of curvature. What is the radius of curvature required if the focal length is to be

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12cm from P. At what point does the beam converge if the lens is a concave lens of focal length

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What is the focal length of a convex lens of focal length 30cm in contact with a concave lens of focal length 20cm? Is the system a converging or a diverging lens? Ignore thickness of the

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A person looking at a person wearing a shirt with a pattern comprising vertical and horizontal lines is able to see the vertical lines more distinctly than the horizontal ones. What is this defect due to? How is such a defect of vision

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Figushows an equiconvex lens (of refractive index 1.50) in contact with a liquid layer on top of a plane mirror. A small needle with its tip on the principal axis is moved along the axis until its inverted image is found at the position of the needle. The distance of the needle from the lens is measured to be 45.0cm. The liquid is removed and the experiment is repeated. The new distance is measured to be 30.0cm. What is the refractive index of the

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A converging lens axially in contact with a diverging lens; both the lenses being of equal focal lengths. What is the focal length of the

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When monochromatic light travels from a rarer to a denser medium, explain the following giving reasons. (i) Is the freguency of reflected and refracted light same as the frequency of incident light?(ii) Does the decrease in speed imply a reduction in the energy carried by light

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A jar of height h is filled with a transparent liquid of refractive index μ (Fig). At the centre of the jar on the bottom surface is a dot. Find the minimum diameter of a disc, such that when placed on the top surface symmetrically about the centre, the dot is

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In the wave picture of light, intensity of light is determined by the square of the amplitude of the wave. What determines the intensity of light in the photon picture of

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Monochromatic light of wavelength 589 nm is incident from air on a water surface. What are the wavelength, frequency and speed of reflected, Refractive index of water is

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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