Subject

Physics

Class

ICSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
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 Multiple Choice QuestionsShort Answer Type

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41.

Voltage applied between cathode and anode of an X-ray tube is 18 kV. Calculate the minimum wavelength of the X-rays produced.


Volatge applied, V = 18 kV

Minimum wavelength,

straight lambda subscript min space equals space hc over eV space equals space 1240 over 18000 space equals space 0.069 space nm
That is,
straight lambda subscript min space equals space 0.69 space straight A with straight o on top, is the minimum wavelength of X-rays produced.

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42.

In a nuclear reactor, what is the function of:

i) The moderator

ii) The control rods

iii) The coolant

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43.

The atomic mass of Uranium straight U presubscript 92 presuperscript 238 is 238.0508 u, while that of thorium Th presubscript 90 presuperscript 234 is 234.0436 u, and that of Helium He presubscript 2 presuperscript 4 is 4.0026 u. Alpha decay converts straight U presubscript 92 presuperscript 238 and Th presubscript 90 presuperscript 234 as shown below.

straight U presubscript 92 presuperscript 238 space rightwards arrow space Th presubscript 90 presuperscript 234 space plus space He presubscript 2 presuperscript 4 space plus space energy
Determine the energy released in this reaction.

ii) What is a neutrino?

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44.

In semiconductor physics, what is meant by:

i) a rectifier
ii) an amplifier
iii) an oscillator

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 Multiple Choice QuestionsLong Answer Type

45.

An alternating emf of 110 V is applied to a circuit containing a resistance R of 80 ohm and inductor L in series. The current is found to lag behind the supply voltage by an angle straight theta space equals space tan to the power of negative 1 end exponent open parentheses 3 over 4 close parentheses. Find the:
i) Inductive Reactance
ii) Impedence of the circuit
iii) Current flowing in the circuit
iv) If the inductor has a coefficient of self inductance of 0.1 H, what is the frequency of the applied emf

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46.

i) What is meant by the dispersive power of a transparent material?

ii) Show that, two thin lenses kept in contact, form an achromatic doublet if they satisfy the condition:

straight omega over straight f plus fraction numerator omega apostrophe over denominator f apostrophe end fraction space equals space 0
where the terms have their usual meanings.

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47.

With the help of a diagram, show how you can use several NAND gates to obtain an OR gate.

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