Q. The bandwidth required for commercial telephonic communication (speech signals) is -
1) 300 MHz
2) 30 kHz
3) 4.2 MHz
4) 2800 Hz
Q. To hear a distinct echo, the time interval between the original sound and the reflected one must be at least -
1) 0.01 s
2) 0.1 s
3) 1.0s
4) 10 s
Q. Which of the following slows down the reaction rate?
1) Heterogeneous catalyst
2) Homogeneous catalyst
3) Catalytic promoter
4) None of the above
Q. Current density is -
1) dimensionless
2) a vector quantity
3) a scalar quantity
4) None of the above
Q. An AC current can be produced by -
1) transformer
2) dynamo
3) choke coil
4) None of the above
Q. Two objects of different masses falling freely near the surface of the Moon would -
1) undergo a change in their inertia
2) have same velocity at any instant
3) experience forces of same magnitude
4) have different accelerations
Q. Which of the following liquids is a bad conductor of electricity?
1) Lemon juice
2) Orange juice
3) Salted water
4) None of the above
Q. A photoelectric cell is a device which -
1) stores light energy
2) converts electric energy into light energy
3) converts light energy into electric energy
4) None of the above
Q. The image formed by the concave mirror is real, inverted, and of the same size as that of the object. The position of the object should be -
1) at the centre of curvature
2) between the focus and centre of curvature
3) beyond the centre of curvature
4) at the focus
Q. Myopia and Hypermetropia can be respectively corrected by -
1) Plano-concave and Cylindrical lens
2) Convex and Concave lens
3) Concave and convex lens
4) Concave and Cylindrical lens