Q1. Bleeding is stopped by the application of alum to a wound because
(a) alum coagulates the blood and forms a clot
(b) alum reduces the temperature near the wound
(c) alum is an antiseptic
(d) the wound is plugged by the alum chunk
Q2. In which of the following cases of motion, are the distance moved and the magnitude of displacement equal?
(a) A car moving in a circular path
(b) A pendulum oscillating to and fro
(c) The Earth revolving around the Sun
(d) A car moving on a straight road
Q3. Bakelite is used in making electrical appliances because it is a
(a) good conductor of heat
(b) good conductor of electricity
(c) good insulator of electricity
Q4. LED and CFL are very commonly used as sources of light in homes. Which of the following statements is true?
(a) LED is better because CFL contains toxic materials
(b) Both are equally good
(c) Neither of them is good because both contain toxic materials
(d) CFL is better because LED contains toxic materials
Q5. The green house effect which is causing an increase in the atmospheric temperature is mainly due to
(b) carbon dioxide
Q6. Hormone Adrenaline
(a) helps the body to adjust stress level when one is very angry or worried
(b) helps control height
(c) helps control balance of electrolytes in the body
(d) helps control level of sugar in the blood
Q7. If the pressure over a liquid increases, its boiling point
(b) does not change
(c) first decreases and then increases
Q8. The thumb of humans moves more freely than other fingers due to the presence of
(a) gliding joint
(b) hinge joint
(c) saddle joint
(d) pivotal joint
Q9. Non-metallic oxides
(a) are basic in nature
(b) are amphoteric in nature
(c) turn red litmus paper blue
(d) are acidic in nature
Q10. A doctor prescribes a medicine to treat hyperacidity. The main ingredient of the medicine is
Sol. When alum is applied to wound, it coagulates the blood and forms a clot. Thus, it stops the bleeding.
Sol. The distance covered and the magnitude of displacement of car moving on a straight road are equal.
Sol. Bakelite is a good insulator, so used in making electrical appliances.
Sol. LED is better because CFL contains toxic materials.
Sol. Carbon dioxide is a green house gas which is responsible for the rise in the temperature of atmosphere.
Sol. As the pressure applied over a liquid increases, the energy needed for the liquid molecules to expand to the gas phase increases. Thus, a higher temperature is required to change from liquid to gas.
Sol. Non-metallic oxides are acidic in nature, thus they turn blue litmus red.
Sol. Weak bases like sodium bicarbonate (NaHCO₃), magnesium hydroxide, magnesium carbonate (MgCO₃), calcium carbonate (CaCO₃), aluminium hydroxide [Al (OH)₃] etc. can be used as a ingredient of the medicine of hyperacidity.
Calcium carbonate (CaCO₃) is an ingredient of antacids like Alcolak, Tums, Quick-Eze etc. while Al(OH)₃ is not so common.