Q. 86. What happens to entropy when a liquid crystallizes into a solid?
(A) Decreases
(B) Increases
(C) Initially decreases then increases
(D) Initially increases then decreases
Answer:
(A) Decreases
Explanation:
Entropy is a measure of randomness or disorder. Solids have a highly ordered crystalline structure compared to liquids, so entropy decreases.
Q. 87. What is the conjugate acid of HCOO-?
(A) CHO
(B) CO2
(C) HCO3-
(D) HCOOH
Answer:
(D) HCOOH
Explanation:
A conjugate acid is formed when a base gains a proton (H+). Adding H+ to the formate ion (HCOO-) gives formic acid (HCOOH).
Q. 88. Entamoeba coli is classified as which type of organism?
(A) Bacterial parasite
(B) Helminthic parasite
(C) Nonpathogenic protozoan
(D) Pathogenic protozoan
Answer:
(C) Nonpathogenic protozoan
Explanation:
Unlike Entamoeba histolytica, Entamoeba coli is a non-pathogenic species of protozoan commonly found existing as a commensal organism in the human gastrointestinal tract.
Q. 89. Which organism shows both plant and animal characteristics?
(A) Bacteria
(B) Euglena
(C) Mycoplasma
(D) Paramecium
Answer:
(B) Euglena
Explanation:
Euglena exhibits characteristics of both plants (it contains chloroplasts and can photosynthesize) and animals (it lacks a cell wall and moves using a flagellum).
Q. 90. A cyclist skids to a stop over 10 m under a 200 N opposing force. How much work does the road do on the bicycle?
(A) 20 J
(B) 200 J
(C) 2000 J
(D) 2100 J
Answer:
(C) 2000 J
Explanation:
Work done is given by Force × distance. W = 200 N × 10 m = 2000 Joules. (Technically it is -2000 J since the force is opposing, but 2000 J indicates the magnitude).
