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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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Magnetic Field of a SolenoidMohan tightly wound a very long copper wire on a PVC pipe and carefully took the pipe out. The two ends of the copper wire then attached to a battery. This cylindrical shape of copper wire showed few properties of a bar magnet. Later he found that it is called a solenoid and this solenoid is used in several devices such as door bell, relay switch etc. The magnetic field of a solenoid is given below.The magnetic field strength of a solenoid having n turns is `B=mu_0nl`, where, `I` is the current flowing in the solenoid.The

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

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Moving Coil GalvanometerMoving coil galvanometer operates on Permanent Magnet Moving Coil (PMMC) mechanism and was designed by the scientist D’arsonval.Moving coil galvanometers are of two types (i) Suspended coil (ii) Pivoted coil type or tangent galvanometer.Its working is based on the fact that when a current carrying coil is placed in a magnetic field, it experiences a torque. This torque tends to rotate the coil about its axis of suspension in such a way that the m agnetic flux passing through the coil is maximum .In a moving coil galvanometer, having a coil of A-turns of area A and carrying

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At the same place, the horizontal component of earth’s magnetic field is 0.40 G and the angle of dip is 30°. What is the resultant magnetic

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

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A current loop behaves as a system of ...................As a result, it acts like an magnetic

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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 presence of magnetic monopoles is ruled out

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

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Assertion: In the phenomenon of mutual induction, self-induction of each of the coils persists. Reason: Self-induction aries when strength of current in same coil changes. In mutual induction, current is changing in both the individual

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In a L-C-R series circuit, the potential difference between the terminals of the inductance is 60 V, between the terminals of the capacitor is 30 V and that across the resistance is 40 V. Then, supply voltage will be equal to

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An L-C-R circuit contains `R=50 Omega, L=1 mH and C = 0.1 muF`. The impedance of the circuit will be minimum for a frequency

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Electrical ResonanceElectrical resonance is said to take place in a series L-C-R circuit when the circuit allows maximum current for a given frequency of the source of alternating supply for which capacitive reactance becomes equal to the inductive reactance. Impedance of this L-C-R circuit is minimum and hence current is maximum. Resonant circuits are used to respond selectively to signals of a given frequency while discriminating against signals of different frequencies. If the response of the circuit is more narrowly peaked around the chosen frequency, we say that the circuit has higher “selectivity or sharpness”. This sharpness is measures with

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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. Which method is used to induce an emf or current in a loop in AC

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In what way does the corrective lens help the above person? Does the lens magnify very distant objects? Explain

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A small pin fixed on a table top is viewed from above from a distance of 50cm. By what distance would the pin appear to be raised if it is viewed from the same point through a 15cm thick glass slab held parallel to the table? Refractive index of glass = 1.5. Does the answer depend on the location of the

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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 lenses. Determine the ‘effective focal length’ of the combination of the two

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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

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A man with normal near point (25 cm) reads a book with small print using a magnifying glass: a thin convex lens of focal length 5 cm. What is the closest and the farthest distance at which he should keep the lens from the page so that he can

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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

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(i) Write the necessary conditions for the phenomenon of total internal reflection to occur. (ii) Write the relation between the refractive index and critical angle for a given pair of optical

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

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Light incident at an angle of incidence of 45° in a certain medium goes grazing along its surface of separation from air after refraction. What is (i) the velocity of light in this medium? (ii) the angle of incidence at which light from air must be incident on this medium so that the refracted ray is normal to the reflected ray? Also, name the special property exhibited by light for this angle of

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What speed should a galaxy move with respect to us so that the sodium line at 589.0 nm is observed at 589.6

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