1071. Which gas is commonly used in balloons and airships ?
A. Hydrogen
B. Helium *
C. Carbon
D. Hydrogen suphide
1072. A slow-running pendulum clock can be speeded up by __________.
A. Increasing the lenght of the rod
B. Increasing the weight of the rod
C. Reducing the length of the rod *
D. Reducing the weight of the rod
1073. A man is standing on a weighing machine in a lift which is moving .The weighing maching will show minimum reading when, the lift is moving ________.
A. Upward with uniform speed
B. Downward with uniform accelaration
C. Upward with uniform acclaration
D. In a free fall due to failure of the lift machanism *
1074. The approximate intensity level of the sound which can caused damage to the ear drum is ________.
A. 20db
B. 60db
C. 100db *
D. 160db
1075. Fuse wire is made of _________.
A. 63% tin and 37% lead *
B. 63% lead and 37% tin
C. 63% tin and 37% alminium
D. 63% lead and 37% aluminium
1076. Which one of the following is the main culprit in the thinning of Ozone layer in the earth’s stratosphere ?
A. Carbon dioxide
B. Choloroflurocarbons
C. Nitrogen oxides *
D. Methane
1077. Steering of a car involves __________.
A. A single force
B. Two forces acting in the same direction.
C. Two forces acting along different lines and in opposite direction
D. A pair of forces acting along the same line and in opposite direction *
1078. The property by virtue of which metals can be beaten into thin sheets is known as __________.
A. Ductility
B. Malleability *
C. Conductivity
D. Density
1079. The sky appears blue because the earth’s atmosphere _________.
A. Scatters blue light
B. Reflects blue light *
C. Transmit blue light
D. Has actual blue cover
1080. The most abundant element in Earth’s crust is _________.
A. Silicon
B. Iron
C. Aluminium
D. Oxygen *