Q1. A lemon sinks in normal water but floats in salty water because the density of
(a) lemon increases in salt water
(b) lemon decreases in salt water
(c) salt water is more than normal water
(d) normal water is more than salt water
Q2. Cooked rice can be preserved for a longer time in a refrigerator because
(a) moisture content in the food is reduced at low temperature
(b) refrigerators contain certain chemicals which kill the microbes
(c) microbes become inactive at low temperature
(d) microbes are destroyed and killed at a low temperature
Q3. An aqueous solution of copper sulphate is acidic in nature because the salt undergoes
(a) Dialysis
(b) Electrolysis
(c) Hydrolysis
(d) Photolysis
Q4. After having been taught about the rich flora and fauna in India, the students of primary classes were taken to Ranthambhore National Park by the school. This would help the students to
(a) develop skills for environmental protection
(b) have fun and enjoy with friends on an outdoor trip
(c) develop respect for nature
(d) co-relate classroom learning to real-life situations.
Q5. In order to introduce the topic on ‘Nutrition’ in class more effectively, a teacher should
(a) give examples of different foods rich in nutrients
(b) draw the diagram of a digestive system on the blackboard
(c) ask the students to open their tiffin boxes, see the contents, followed by teacher’s explanation
(d) None of these
Q6. The process of separating a crystalloid, from a colloid by filtration, is called-
(a) Emulsification
(b) Dialysis
(c) Coagulation
(d) None of these
Q7. Dialysis can separate which of the following in addition to the glucose from human blood-
(a) Fructose
(b) Starch
(c) Protein
(d) Sucrose
Q8. The movement of colloidal particle under the influence of electric filed is called-
(a) Electro-dialysis
(b) Electro-osmosis
(c) Electrolysis
(d) Electrophoresis
Q9. When a strong beam of light is passed through a colloidal solution, the light is-
(a) Reflected
(b) Scattered
(c) Both (a) & (b)
(d) None of these
Q10. The bleeding of a wound is stopped by the application of ferric chloride because-
(a) Blood starts flowing in the opposite direction
(b) Ferric chloride seals the blood vessels
(c) Blood reacts and a solid is formed which seals the blood vessels
(d) Blood is coagulated and the blood vessels are sealed
Solutions:
S1. Ans.(c)
S2. Ans.(c)
S3. Ans.(c)
S4. Ans.(d)
S5. Ans.(d)
S6. Ans.(b)
S7. Ans.(c)
S8. Ans.(d)
S9. Ans.(b)
S10. Ans.(d)
