If the momentum of a body increases from 10 units to 25 units in 5 sec, then the force acting on it is

• 1 unit
  
  

• 2 units
  
  

• 3 units
  
  

• 4 units

Sound waves consist of 20 compressions and 20 rarefactions in 10m length. The wavelength of the waves is

• 25cm
  
  

• 50cm
  
  

• 75cm
  
  

• 100cm

The decimal equivalent of the binary number (1101)₂ is

• 9

• 11

• 13

• 15

In which of the following cases of motion, are the distance moved and the magnitude of displacement equal?

• A car moving in a circular path

• A pendulum oscillating to and fro

• The Earth revolving around the Sun

• A car moving on a straight road

LED and CFL are very commonly used as sources of light in homes. Which of the following statements is true?

• LED is better because CFL contains toxic materials

• Both are equally good

• Neither of them is good because both contain toxic materials

• CFL is better because LED contains toxic materials

If the pressure over a liquid increases, its boiling point

• increases

• does not change

• first decreases and then increase

• decreases

A feather weighing 5 g and a nail weighing 10 g have the same kinetic energy. Which of the following statements is true about the momentum of the two bodies?

• The heavier body will have higher momentum

• Both will have equal momentum

• It is not possible to compare the momentum of two objects

• The lighter body will have higher momentum

Most Boards of Education have banned the dissection of animals because

• procuring animals has become an expensive proposition

• there is a need to sensitise students to prevention of cruelty to animals

• they may spread new diseases

• animals are no longer available for dissection

19.

The SI unit of calorific value is

• J/kg

• Kilocalorie/kg

• kJ/kg

• Calorie

If the frequency of vibrations of a body is decreased and its amplitude is increased, then

• pitch increases but loudness decreases

• pitch decreases but loudness increases

• both pitch and loudness of sound produced will increase.

• both pitch and loudness of sound produced will decrease