1. Light from Sun reaches Earth in approximately
a) 3 minutes
b) 8 minutes
c) 10 minutes
d) 12 minutes
Explanation: Light from Sun reaches Earth in approximately 8 minutes.
2. Through which light cannot pass?
a) Notebook paper
b) water
c) Book
d) Sun glasses
Explanation: Light cannot pass through book.
3. The speed of light in air is
a) 3 × 108 m/s
b) 3 × 10–8 m/s
c) 8 × 103 m/s
d) Infinity
Explanation: The speed of light in air is 3 × 108 m/s.
4.Eclipses occur due to which optical phenomena?
a) Reflection
b) Refraction
c) Rectilinear propagation
d) Diffraction
Explanation: Eclipses occur due to rectilinear propagation of light.
5.When a bottle of scent is kept open in a corner of a room its odour is felt in all parts of the room. This is due to the phenomenon of :
a) Evaporation
b) Vaporisation
c) Diffusion
d) Sublimation
Explanation: When a bottle of perfume is opened in a corner of a room, the scent soon spreads all over the room. This physical procedure is called diffusion, due to which the liquid or gaseous molecules travels from the area of higher density to that of the lower density of that substance.
6. The unit of force is a
a) Derived Unit
b) Basic Unit
c) Fundamental Unit
d) None of the above
Explanation: The unit of force is a derived unit.
7. Atmospheric pressure exerted on earth is due to
a) Gravitational pull
b) Rotation of earth
c) Revolution of earth
d) Uneven heating of earth
Explanation: Atmospheric pressure is caused by the gravitational attraction of the planet on the atmospheric gases above the surface, and is a function of the mass of the planet, the radius of the surface, and the amount and composition of the gases and their vertical distribution in the atmosphere.
8. What is the SI unit of Force?
a) pascal
b) Boyle
c) Newton
d) Watt
Explanation: SI unit of force is Newton.
9. What measures Air pressure?
a) Barkometer
b) Bolometer
c) Spectrometer
d) Barometer
Explanation: Barometer measures air pressure.
10. The rice is cooked more quickly in a pressure cooker because
a) It is covered.
b) Less quantity of water is used.
c) None of these
d) Water boils at a higher temperature under pressure.
Explanation: Food is cooked more quickly in a pressure cooker because at the higher pressure (1 bar/15 psi), the boiling point of water rises from 100°C (212°F) to 121°C (250°F). The hotter steam is able to transmit its thermal energy to the food at around 4 times the rate of conventional boiling.