751. The band theory of solids explains satisfactorily the nature of_________________?
A. Electrical insulators alone
B. Electrical conductors alone
C. Electrical semi conductors alone
D. All of the above

752. A completely filled band is called__________________?
A. Conduction band
B. Valence band
C. Forbidden band
D. Core band

753. Which one has the greatest energy gap ?
A. Semi conductor
B. Conductor
C. Metals
D. Non metals

754. With increase in temperature the electrical conductivity of intrinsic semi conductor___________________?
A. Decreases
B. Increases
C. Remains same
D. First increases then decreases

755. On the basis of band theory of solids the semiconductors have _____________________?
A. A party filled valence band and totally empty conduction band
B. A completely filled valence band a totally empty conduction band and a very wide forbidden band
C. A completely filled valence band a partially filled conduction band and a narrow forbidden band
D. A partly filled valence band a totally empty conduction band and a wide forbidden band

756. Very weak magnetic fields are detected by___________________?
A. Squids
B. Magnetic resonance imaging (MRI)
C. Magnetometer
D. Oscilloscope

757. Energy needed to magnetize and demagnetize is represented by _________________?
A. Hysteresis curve
B. Hysteresis loop area
C. Hysteresis loop
D. Straight line

758. What is the SI unit of modulus of elasticity of substance ?
A. Nm-2
B. Jm-2
C. Nm-1
D. Being a number it has no unit.

759. A rubber cord of cross-sectional area 2cm2 has a length of 1m. When a tensile force of 10N is applied the length of the cord increases by 1cm. What is the youngs modulus of rubber ?
A. 2×108 Nm-2
B. 5×106 Nm-2
C. 0.5×10-6 Nm-2
D. 0.2×10-6Nm-2

760. A uniform steel wire of length 4m and area of cross-section 3×10-6m2 is extended by 1mm by the application of a force. If the youngs modulus of steel is 2×1011 Nm-2 the energy stored in the wire is___________________?
A. 0.025J
B. 0.50J
C. 0.75J
D. 0.100J

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