When two forces act along the same direction on an object, then the net force acting on the object is ____ of the two forces.
A) the average
B) less than the sum
C) greater than the sum
D) equal to the sum
Two objects, A and B, one over the other, are moving with the same velocity. Which of the following statements is correct?
A) Friction on A is in the forward direction.
B) Friction on A is in the backward direction.
C) Friction on B is in the forward direction.
D) No friction acts between A and B.
If an object oscillates 80 times per second, it is said to have a frequency of ____.
A) 80 sec
B) 80 Hz
C) 80 hr
D) 0.0125 Hz
A tester is used to test the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows bright for liquid A, while it glows very dimly for liquid B. We can conclude that liquid A is a better conductor than liquid B.
Tremors on the earth can also be caused when a volcano erupts, or a meteor hits the earth, or an underground nuclear explosion is carried out.
An aluminium foil with a hole is placed just below the base of a candle flame and above the melted wax. The candle is extinguished because the ____.
A) aluminium foil cuts off the supply of oxygen to the burning flame
B) aluminium foil cuts off the flow of molten wax to the wick
C) aluminium foil conducts away the heat, and the temperature falls below ignition temperature
D) aluminium foil cuts off the supply of of nitrogen
Which of the following is not an attribute of a good domestic fuel?
A) Fairly cheap and easily available
B) Moderate rate of combustion
C) Low calorific value
D) Safe to handle, store and transport
Zn + CuSO4 → ZnSO4 + Cu is a ____ reaction.
The development of a moustache at the age of 11-18 is a sign of ____.
C) hormonal imbalance
Which of the following micro-organism has the ability to fix nitrogen?