Physics1. On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because
A. mercury is a metal
B. density of mercury is greater than that of water
C. cohesion of mercury is greater than its adhesion with glass
D. cohesion of water is greater than its adhesion with glass
Answer: Option (C)
2. Suitable impurities are added to a semiconductor depending on its use. This is done in order to
A. increase its life
B. enable it to withstand higher voltages
C. increase its electrical conductivity
D. increase its electrical resistivity
Answer: Option (C)
3. Stars twinkle because
A. the intensity of light emitted by them changes with time
B. the distance of the stars from the earth changes with time
C. the refractive index of the different layers of the earth's atmosphere changes continuously, consequently the position of the image of a start changes with time
D. the light from the star is scattered by the dust particles and air molecules in the earth's atmosphere
Answer: Option (C)
4. It takes much longer to cook food in the hills than in the plains, because
A. in the hills the atmospheric pressure is lower than that in the plains and therefore water boils at a temperature lower than 100oC causing an increase in cooking time
B. due to low atmospheric pressure on the hills, the water boils at a temperature higher than 100oC and therefore water takes longer to boil
C. in the hills the atmospheric density is low and therefore a lot of heat is lost to the atmosphere
D. in the hills the humidity is high and therefore a lot of heat is absorbed by the atmosphere leaving very little heat for cooking
Answer: Option (A)
5. Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?
A. Water, iron and air
B. Iron, air and water
C. Air, water and iron
D. Iron, water and air
Answer: Option (C)
Chemistry1. The most abundant rare gas in the atmosphere is
A. He
B. Ne
C. Ar
D. Xe
Answer: Option (C)
2. The Latin word formica means ant. The name formic acid is derived from this Latin word because
A. this acid, in ancient times, was used to eliminate ant-hills
B. this corrosive acid is secreted by ants to drive away their enemies
C. this acid was first obtained by the distillation of ants
D. ants are attracted by the odour of this acid
Answer: Option (C)
3. The ore which is found in abundance in India is
A. monazite
B. fluorspar
C. bauxite
D. magnetite
Answer: Option (A)
4. The inherited traits of an organism are controlled by
A. RNA molecules
B. nucleotides
C. DNA molecules
D. enzymes
Answer: Option (C)
5. The heat energy produced when the human body metabolises 1 gram of fat is
A. 30 KJ
B. 1 KJ
C. 39 KJ
D. 29 KJ
Answer: Option (C)
Life Sciences1. If the radius of blood vessels of a person decreases his/her blood pressure will
A. Decrease
B. Increase
C. Remain Same
D. Becomes zero
Answer: Option (B)
2. Cell or tissue death within a living body is called as :
A. Neutrophilia
B. Nephrosis
C. Necrosis
D. Neoplasia
Answer: Option (C)
3. The main use of salt in the diet is to :
A. ease the process of cooking
B. increase the taste
C. produces a small amount of hydrochloric acid required for digestion
D. increased the solubility of food particles in water
Answer: Option (C)
4. Typhoid is caused by :
A. Pseudomonas sp.
B. Staphylococcus
C. Bacillus
D. Salmonella typhi
Answer: Option (D)
5. Fresh Yeast cells are a good source of :