Physics | RJ Board | Grade 12 | 2014
Q. Two concentric circular coils of radii r and R are placed coaxially with centres coiciding. If R >> r then calculate the mutual inductance between the coils.
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Q. Two cells of emfs E1 and E2 are connected in series. Their internal resistances are r1 and r2 respectively. Compute the equivalent emf and equivalent internal resistance.
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Q. A ball of mass 0.12 kg is moving with a speed 20 m/s. Calculate the de Broglie wavelength. (Planck constant h=6.62×1034J.s)
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Q. Write the names of two universal logic gates. What is integrated circuit? Write two advantages of it.
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Q. Is Young's double-slit experiment, the slots are separated by 0.28 mm and the screen is placed 1.4 m away. If the distance between the central bright fringe and the fourth bright fringe is 1.2 cm, determine the wavelength of light used in the experiment.
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Q. From the equation R=RoA13, show that the nuclear matter density is nearly constant. [Where Ro is a constant and A is the mass number.]
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Q. The energy of the electron in the ground state of hydrogen atom is -13.6 eV. Find the kinetic energy and potential energy of electron in this state.
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Q. The graph between the stopping potential V0 and frequency v for two different metal plates P and Q are shown in the figure. Which of the metals has greater threshold wavelength and work function?

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Q. Define resolving power of microscope. Write its formula. How will it vary, when
(a) wavelength of incident light is decreased?
(b) aperture of the objective lens is decreased?
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Q. If magnetic monopoles would have existed. How would the Gauss' law of magnetism be modified?
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Q. A carbon resistor has a value of 62×103Ω with a tolerance of 5%. Write colour code for this resistor in sequence.
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Q. Write the names of two important processes which occur on formation of p-n junction. Define the 'depletion region' and 'potential barrier' in it.
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Q. A monochromatic light source of frequency 6×1014Hz is emitting energy at the rate 2×103J/s. Calculate the number of photons emitted per second by the source.
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Q. Write the names of any two organic compound semiconductors.
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Q. How may times total internal reflection occurs in the drop for formation of primary and secondary rainbows?
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Q. Two point charges 5×108C and 3×108C are located 16 cm apart. At what point on the line joining these charges the electric potential will be zero?
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Q. Sketch a block diagram of a generalised communication system
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Q. Define electric flux. Apply Gauss' law to obtain an expression for the electric field intensity at a point due to an infinitely long uniformly charged straight wire. Draw the necessary diagram.
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Q. Obtain the equation J=σE of Ohm's law on the basis of drift velocity. (Where symbols carry their usual meanings).
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Q. Draw a curve for showing variation in alternating current with frequency in LCR resonant circuit. Hence obtain an expression of bandwidth.
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Q. What are diamagnetic substances? Give one example
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Q. Write the definition of wavefront.
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Q. A bar magnet NS is moved in the direction indicated by an arrow between two coils AB and CD as shown in the figure. In which coil the direction of current will look like anti-clockwise if viewed from left side?

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Q. Draw the circuit diagram of npn transistor in common emitter configuration. Hence describe the working method to obtain output characteristic curve.
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Q. An object of size 3 cm is placed at 30 cm in front of a concave mirror of radius of curvature 40 cm. Find the distance and size of image from the mirror and describe the nature of the image
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Q. The decay constant of a radioactive substance is 0.693 per minute. What will be the half-life and mean life of it?
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Q. Write the mathematical equation of 'Ampere-Maxwell law'.
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Q. Identify the constituent radiations of electromagnetic spectrum which
(a) is obsorbed by ozone layer in the atmosphere
(b) i produced by bombarding a metal target by high speed electrons
(c) is used in satellite communication
(d) has wavelength range between 400 nm to 700 nm.
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Q. Write one example of point to point communication.
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Q. State any two reasons for necessity of modulation.
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