Important Questions and Answers
Q: Sketch the diagram of a Nuclear Reactor showing various parts. (5 Marks)
A: Parts: 1. Fuel rods; 2. Moderator (Water); 3. Control rods; P: Pump; H.E: Heat exchange part; S: Exit for steam; W: Inlet for
water; Sh: Lead chamber; RC: Reactor core
Q: Draw a neat diagram showing the extraction of Magnesium from its ore and label its various parts. (5 Marks)
A: Parts: 1. Iron cell; 2. Magnesium; 3. Graphite anode; 4. Porcelain hood; 5. Iron cathode; 6. Coal gas; 7. Chlorine; 8. Coal
gas; 9. Molten electrolyte
Q: State the properties and uses of a junction diode. (4 Marks)
A: Properties of p-n junction diode: 1. A p-n junction diode conducts electricity in forward bias condition and offers low resistance for current flow.
2. In the reverse bias condition, it offers a high resistance and no current flows in the circuit. Uses of p-n junction diode: 3. A p-n junction diode can be used as an electronic switch.
4. In a rectifier circuit, a p-n junction diode is used to convert Alternating Current (AC) in to Direct Current (DC). This conversion is utilized in power supply devices found in electronic appliances such as TV, radio, computers, tape recorders etc.
5. Certain p-n diodes glow on supply of electricity. Such diodes are called Light Emitting Diodes (LEDs). These are used in digital
clocks and digital (electronic) calculators.
Q: How do you test the quality of a soap? (4 Marks)
A: Soap is a Sodium or Potassium salts of fatty acids of long carbon
chains (or) soaps are salts of fatty acids.
Testing: 1. Dissolve 1.5 gm. of soap in 100 ml of distilled or soft water.
2. Take 10 ml of this soap solution in a boiling test tube.
3. Close the tube with a rubber stopper and shake vigorously for 15 seconds. Allow the solution to stand for 30 seconds. Observe the
level of foam.
4. Perform the same experiment on different kinds of soaps available in the market. A good soap is that which gives the largest
lather or of greatest height.
Q: State the characteristics of simple harmonic motion. (2 Marks)
A: The characteristics of SHM are 1. The motion of the particle
is vibratory about a mean position.
2. The acceleration of the particle is always directed towards the mean position. 3. The magnitude of acceleration (a) is directly proportional to the displacement (x) of the particle from its equilibrium position i.e.: a ∝ −x.
Q: Define Resonance. (1 Mark)
A: Resonance is the phenomenon in which if one of the two bodies of the same natural frequency is set into vibrations, the other body also vibrates under the influence of the first body.
Q: Write the Pauli's exclusion principle. (1 Mark)
A: 1. No two electrons will have all the four quantum numbers equal.
2. In an orbital, maximum number of electrons are 2.
I. Fill in the blanks with suitable word or words (1/2 Mark each)
1. When a body is projected towards the earth, the acceleration due to gravity is taken as....
2. The susceptibility (x) of a diamagnetic substance is ....
3. Particles undergo maximum displacement at ..... in a stationary wave.
4. The equivalent resistance of two resistors 6Ω, 12Ω when connected in series is .....
5. The unit of self inductance is .....
6. The colour of methyl orange indicator in acidic medium is .....
7. Chief component of cooking gas is ....
8. .... metal gives peroxide in addition to oxide when burnt in excess of oxygen.
9. The number of subshells present in L- shell are ....
10. H2SO4 + Ca(OH)2 → ...... + H2O
II. Match the following. (1/2 Mark each) Group A Group B
1. Atomic number ( ) A) Stability of atom
2. Moss defect ( ) B) amu
3. Mass number ( ) C) Number of protons
4. Unit of atomic ( ) D) Ev mass
5. Unit of energy ( ) E) Sum of the number of protons and neutrons
Answers: I. 1) positive 2) very low and negative 3) antinode 4) 18 Ω 5) Henry 6) Red 7) Butane 8) Barium 9) 2 10) CaSO4.
II. 1-C; 2-A; 3-E; 4-B; 5-D.