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ISC Class 12 Physics Solved Question Paper 2011

Short Answer Type

21. Three capacitors each of capacitance C are connected in series. Their equivalent capacitance is Cs. The same three capacitors are now connected in parallel. Their equivalent capacitance becomes C_P find the ratio

open parentheses straight C subscript straight P over straight C subscript straight S close parentheses

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22. i) A galvanometer with a resistance of 75 Ω produces a full scale deflection with a current of 5 mA. How can this galvanometer be converted into an ammeter which has a range 0 - 5A?
ii) Explain the statement: temperature coefficient of resistance of a metal is 4 x 10^-3/ ⁰C.

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23. In the circuit shown below Figure 3, E₁ and E₂ are batteries having emfs 4.0 and 3.5 V respectively and internal resistance 1Ω and 2Ω respectively. Using Kirchoff s laws, calculate currents : I₁, I₂ and I₃.

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24. Show with help of a labelled graph, how thermo emf ‘e’ developed by a thermocouple varies with θ, the temperature difference between the two junctions. On the graph, mark neutral temperature as θ_N and temperature of inversion as θ₁.

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25.

(i) What is meant by a paramagnetic substance? State Curie’s law.

(ii) What is the value of magnetic susceptibility of Aluminium of its relative permeability is 1.000022?

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26. Using Ampere’s circuital law or Biot and Savart’s law, show that magnetic flux density ‘B’ at a point ‘P’ at a perpendicular distance ‘a’ from a long current carrying conductor is given by:

straight B space equals space open parentheses fraction numerator straight mu subscript straight o over denominator 4 straight pi end fraction close parentheses space fraction numerator 2 straight I over denominator straight a end fraction

(Statement of the laws - not required)

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27. A current of 4A flows in a coil when it is connected to a 12V dc source. When the same coil is connected to an AC source (12 V, 8 Hz), a current of 2-4 A flows in the coil. Calculate coefficient of self-inductance (L) of the coil.

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28.

How much force per unit length acts on a long current carrying conductor X due to a current flowing through another similar conductor Y, kept parallel to it in vacuum ?

Use this equation to define an Ampere, the fundamental unit of current.

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29.

(i) Arrange all the seven types of electro-magnetic radiations in increasing order of their frequencies. (You must begin with a radiation with lowest frequency and end with the one having the highest frequency.)

(ii) State how electric vector E, magnetic vector B and velocity vector C are oriented in an electromagnetic wave.

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30. In Young’s double slit experiment, using monochromatic light L, of wavelength 700 nm, With bright fringe was obtained at a certain point P on a screen. Which bright fringe will be obtained at the same point P if monochromatic light of wavelength 500 nm is used in place of LI (No other alterations were made in the experimental set up).

Given:

λ₁= 700nm, 10^th bright fringe.

λ₂ = 500 nm, n² = ?

We know,
n₁ λ₁= n₂λ₂

n₂= $fraction numerator straight n subscript 1 straight lambda subscript 1 over denominator straight lambda subscript 2 end fraction space equals space fraction numerator 10 space x space 700 over denominator 500 end fraction space equals space 14$