Multiple Choice Questions on Physics and Chemistry

20. Read the given statements and select the correct option.

Statement 1: Mountaineers often encounter problems like nose bleeding on reaching high altitudes.

Statement 2: Atmospheric pressure increases with increasing altitude.

A. Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1.

B. Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1.

C. Statement 1 is true but statement 2 is false.

D. Both statements 1 and 2 are false.

21. When a conducting sphere $A$ on an insulating stand, is brought near a positively charged light sphere $B$ hanging from a nylon thread, the sphere $B$ is attracted to $A$. Which of the following conclusions about the sphere $A$ is correct?

A. Sphere $A$ is neutral.

B. Sphere $A$ is positively charged.

C. Sphere $A$ is negatively charged.

D. Sphere $A$ is either negatively charged or neutral.

22. Match column I with column II and select the correct option from the given codes.

Column I

P. Burning of LPG

Q. Burning of crackers

R. Rusting of iron

S. Burning of sodium

Column II

(i) Explosion

(ii) Slow combustion

(iii) Spontaneous combustion

(iv) Rapid combustion

A. P - (i), Q - (iii), R - (iv), S - (ii)

B. P - (iv), Q - (iii), R - (ii), S - (i)

C. P - (iv), Q - (i), R - (ii), S - (iii)

D. P - (iii), Q - (ii), R - (i), S - (iv)

23. Match column I with column II and select the correct option from the given codes.

Column I (Molecule)

P. Carbon monoxide ($C:O$)

Q. Hydrochloric acid ($H:Cl$)

R. Carbon dioxide ($C:O$)

S. Nitrogen dioxide ($N:O$)

Column II (Mass ratio of elements)

(i) $1:35.5$

(ii) $3:4$

(iii) $7:16$

(iv) $3:8$

A. (P)-(ii), (Q)-(i), (R)-(iv), (S)-(iii)

B. (P)-(iii), (Q)-(ii), (R)-(i), (S)-(iv)

C. (P)-(i), (Q)-(iv), (R)-(iii), (S)-(ii)

D. (P)-(iv), (Q)-(iii), (R)-(ii), (S)-(i)

24. Two plane mirrors are placed at an angle of $60^\circ$ as shown in the given figure. The number of images of the point object $O$ is

A. 3

B. 6

C. 7

D. 5

This question includes visual content: Question 24 includes a diagram showing two plane mirrors intersecting at an angle marked as $60^\circ$. A point object labeled 'O' is placed in the angular space between the two mirrors. The mirrors are represented by lines with hatching on the non-reflective side.