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A transformer with turns ratio `N_1/N_2=50/1` is connected to a `120 V' 'AC` supply. If primary and secondary circuit resistances are `1.5 kOmega and 1Omega` respectively, then find out power of

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

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In an L-C-R series circuit, the voltage across each of the components L, C and R is 100 V. The voltage across the LC combination will

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Assertion: Average value of current in half the cycle of an AC circuit cannot be zero. Reason: For positive half cycle average value of current is `(i_0)/pi`, where `i_0` is the peak value

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

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Assertion: In series, L-C-R circuit, voltage across capacitor is always less than the applied voltage. Reason: In series L-C-R circuit,

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Assertion: Resonance phenomenon is exhibited by a circuit only, if both L and C are present in the circuit.Reason: Voltage across L & C does not cancel each other and the current amplitude is `V_m'/' R`, the total source voltage appearing across R causes

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Assertion: A capacitor of suitable capacitance can be used in an AC circuit in place of the choke coil. Reason: A capacitor blocks DC and allows AC

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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

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.A transformer has 150 turns in its primary and 1000 in secondary. If the primary is connected to

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

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Suppose while sitting in a parked car, you notice a jogger approaching towards you in the side view mirror of R = 2 m. If the jogger is running at a speed of 5 m s–1, how fast the image of the jogger appear to move when the jogger is

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A convex lens has 20 cm focal length in air. What is focal length in water? (Refractive index of air-water = 1.33, refractive index for air-glass =

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The above person prefers to remove the spectacles while looking at the sky. Explain

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A tank is filled with water to a height of 12.5 cm. The apparent depth of a needle lying at the bottom of the tank is measured by a microscope to be 9.4 cm. What is the refractive index of water? If water is replaced by a liquid of refractive index 1.63 up to the same height, by what distance would the microscope have to be moved to focus on the needle

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Use the mirror equation to deduce that: a convex mirror always produces a virtual image independent of the location of the

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How does focal length of a lens change when red light incident on it is replaced by violet light? Give reason for your

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(i) State the principle on which the working of an optical fibre is based. (ii) What are the necessary conditions for this phenomenon to

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(i) A mobile phone lies along the I principal axis of a concave mirror. Show with the help of a suitable diagram, the formation of its image. Explain whymagnification is not a uniform, (ii) Suppose the lower half of the concave mirror's reflecting surface is covered with an opaque material. What effect this will have on the image of the object?

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What is the effect on the interference fringes in a Young’s double-slit experiment due to: the width of the source slit is

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In Young’s double-slit experiment using monochromatic light of wavelength λ, the intensity of light at a point on the screen where path difference is λ, is K units. What is the intensity of light at a point where path difference is

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Light of wavelength 5000 Å falls on a plane reflecting surface. What are the wavelength and frequency of the reflected light? For what angle of incidence is the reflected ray normal to the incident

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In double-slit experiment using light of wavelength 600 nm, the angular width of a fringe formed on a distant screen is 0.1°. What is the spacing between the two

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

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