CBSE CHALLENGE QUIZ

Transpiration has been described as a ‘necessary evil’ because it is inevitable, but potentially harmful. Which of the following are the after-effects of transpiration?

(i) Absorption of mineral salts.

(ii) Regulation of plant temperature.

(iii) Energy deficit and injury in plants.

(iv) Ascent of sap.

• (i) & (iv)

• (i) & (iii)

• (i), (ii) & (iii)

• (i), (ii) & (iv)

A simplified food chain for an aquatic environment is shown below: algae → mosquito larvae → small fish → large fish If the number of mosquito larvae suddenly increased, the food chain would be affected. Analyze the following consequences and select from the choices what would be the impact?\

I. The number of small fish would increase.

II. The number of large fish would decrease.

III. The number of large fish would increase.

IV. Amount of algae would decrease.

• Only I

• Only IV

• Both I and IV

• Both II and IV

A roller coaster begins at rest from point A, 120 m above the ground, as shown in figure. Assume that no energy is lost from the coaster to frictional heating, air resistance, sound, or any other process. The radius of the loop is 40 m. (take g=10 m/s² ). The speed of the roller coaster at points B and D are respectively

• 34 m/s, 28 m/s

• 28 m/s, 34 m/s

• 17 m/s, 14 m/s

• 17 m/s, 0

Chlorine gas reacts with _______ to form bleaching powder.

• dry slaked lime

• dil. solution of Ca(OH)₂

• conc. solution of Ca(OH)₂

• dry calcium oxide

Baking powder is different from baking soda as it also contains a small quantity of edible acid. The presence of the edible acid decreases bitterness of baking soda. Which acid is present in baking powder?

• sulphuric acid

• acetic acid

• tartaric acid

• malic acid

Hawks and eagles are often reported to die due to pesticide poisoning, but pigeons are not. The phenomenon responsible for this is:

• Eutrophication

• Pollution

• Biomagnification

• Accumulation

Figure here shows speed-time graph for a car moving in a straight line. At which point is its acceleration non-uniform?

• A

• B

• C

• D

The angle of incidence on mirror B is

• 20⁰

• 50⁰

• 60⁰

• 70⁰

Potassium iodide and lead nitrate solutions are mixed in a test tube to form lead iodide and potassium nitrate. Which of the following correctly represents/represent the type/types of the reaction (s) involved?

i) Displacement reaction

ii) Precipitation reaction

iii) Combination reaction

iv) Double displacement reaction

• iv only

• ii only

• both i and ii

• both ii and iv

Four aluminum rods A, B, C & D of different dimensions are given in the picture. Which will have the least resistance?

• A

• B

• C

• D