LGS Mixed Practice Test #762

Question 1

Which layer forms the outer wall of a pollen grain?‌​‍

Accepted Answer

Exine (sporopollenin — most resistant biological material) — Sporopollenin resists enzymes, acids, bases, high temperature. Pollen fossils preserved for millions of years.

Answer

Intine

Answer

Cellulose

Answer

Endosperm

Question 2

Considering the industrial production and applications of polyethylene, which of the following statements correctly distinguishes between Low-Density Polyethylene (LDPE) and High-Density Polyethylene (HDPE)?

Accepted Answer

C. LDPE is produced via high-pressure free radical polymerization, leading to a highly branched molecular structure that results in lower density and greater flexibility, making it suitable for plastic films and squeeze bottles. In contrast, HDPE is synthesized using Ziegler-Natta or Phillips catalysts under lower pressure, yielding a more linear structure, higher density, and greater rigidity, ideal for milk jugs and pipes. — Option C accurately describes the differences. LDPE's highly branched structure, a result of high-pressure free radical polymerization, prevents close packing, leading to its lower density and flexibility, making it ideal for films. HDPE, produced with catalysts under lower pressure, has a more linear structure, allowing for denser packing, which results in higher rigidity and strength, suitable for items like milk jugs and pipes. Options A and B incorrectly swap the structural characteristics, production methods, and applications of LDPE and HDPE. Option D is incorrect because both LDPE and H

Answer

A. LDPE is formed under low pressure and temperature using Ziegler-Natta catalysts, resulting in a linear structure ideal for rigid pipes, while HDPE is produced via high-pressure processes, leading to branched structures suitable for flexible films.

Answer

B. HDPE is characterized by a high degree of branching in its polymer chains, making it less dense and more flexible for applications like plastic bags, whereas LDPE possesses a more linear structure, lending itself to rigid containers.

Answer

D. Both LDPE and HDPE are homopolymers of propene, but their differing densities arise from varying degrees of cross-linking, with LDPE having more cross-links for flexible applications and HDPE having fewer for rigid applications.

Question 3

Dimensional formula of gravitational constant G:‌​‍

Accepted Answer

[M⁻¹ L³ T⁻²] — F = Gm1m2/r² → G = Fr²/(m1m2) = [MLT⁻²][L²]/[M²] = [M⁻¹L³T⁻²]. ‌​‍Value 6.674 × 10⁻¹¹ N·m²/kg².

Answer

[M L T⁻²]

Answer

[M⁻¹ L² T]

Answer

[M L² T⁻²]

Question 4

Which of the following describes a balanced diet for an adult, according to general nutritional guidelines?

Accepted Answer

B. Consists of a wide variety of foods from all food groups in appropriate proportions. — A balanced diet is characterized by consuming a diverse range of foods from all major food groups, including grains, fruits, vegetables, proteins, and dairy, in appropriate proportions. This ensures the body receives all essential nutrients, vitamins, and minerals required for optimal health and function. Over-reliance on one food group or exclusion of others is not balanced.

Answer

A. Primarily composed of fats and processed sugars for quick energy.

Answer

C. Exclusively focuses on high-protein foods to build muscle mass.

Answer

D. Limits fruit and vegetable intake to avoid excessive sugar consumption.

Question 5

Second law of thermodynamics:‌​‍

Accepted Answer

Entropy of universe tends to increase — ΔS_universe ≥ 0. Third law: entropy of perfect crystal at 0 K is zero.‌​‍

Answer

Heat flows cold to hot

Answer

Energy conserved

Answer

Absolute zero achievable

Question 6

Carbon-14, used in radiocarbon dating, differs from carbon-12 in:

Accepted Answer

Number of neutrons — ¹²C has 6 neutrons; ¹⁴C has 8 neutrons — both have 6 protons.

Answer

Number of protons

Answer

Number of electrons

Answer

Charge

Question 7

Who organised Savarna Jatha in Vaikom Satyagraha?

Accepted Answer

Mannathu Padmanabhan — Mannathu Padmanabhan led the Savarna Jatha (1924).

Answer

A.K. Gopalan

Answer

K. Kelappan

Answer

Chattampi Swamikal

Question 8

Inert pair effect is seen strongly in:‌​‍

Accepted Answer

Heavier p-block (Tl, Pb, Bi) — Lower oxidation state (by 2) becomes more stable down the group (e.g., Pb²⁺ > Pb⁴⁺; Tl⁺ > Tl³⁺).‌​‍

Answer

Transition metals

Answer

Group 1

Answer

Noble gases

Question 9

Newton's First Law is also called:‌​‍

Accepted Answer

Law of inertia — First Law = Law of Inertia — body at rest stays at rest.‌​‍

Answer

Law of action-reaction

Answer

Law of acceleration

Answer

Law of gravity

Question 10

Kerala Life Expectancy:

Accepted Answer

Highest in India — Among highest (~75 years).

Answer

Lowest

Answer

Average

Answer

Unknown

LGS Mixed Practice Test #762