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

Mica is used in cooking utensils because it is

• good conductor of heat but bad conductor of electricity
  
  

• bad conductor of heat but good conductor of electricity
  
  

• good conductor of both heat and electricity
  
  

• bad conductor of both heat and electricity

The angle of dip at magnetic pole of earth is

• 0°
  
  

• 45°
  
  

• 90°
  
  

• 135°

24.

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

• 25cm
  
  

• 50cm
  
  

• 75cm
  
  

• 100cm

If $\frac{4}{3}$ and $\frac{3}{2}$ be respectively the absolute refractive indices of water and glass, then the refractive index of glass relative to water is

• $\frac{8}{9}$

• $\frac{9}{8}$

• $\frac{4}{3}$

• $\frac{3}{4}$

In household wiring, what is the colour of 'earth wire'?

• Red
  
  

• Green
  
  

• Black
  
  

• White

Kirchhoff's current law is based on the conservation of

• energy
  
  

• momentum
  
  

• charge

• mass

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

• 9

• 11

• 13

• 15

Which of the following is not a constituent of petroleum?

• Petrol
  
  

• Coke
  
  

• Paraffin wax
  
  

• Lubricating oil

A metal M does not liberate hydrogen from acids but reacts with oxygen to give a black colour product. Identify M.

• Na
  
  

• Mg
  
  

• Cu
  
  

• Ca