General Science - MCQ Practice Questions

Abscisic acid (ABA) promotes seed dormancy and inhibits germination, acting antagonistically to gibberellins which promote germination.

Osmosis is passive transport of water molecules across a semipermeable membrane in response to water potential differences.

Ethylene is the major hormone controlling senescence (aging) in plants, promoting leaf yellowing, fruit ripening, and abscission.

Nitrosomonas is a chemosynthetic bacterium that oxidizes ammonia to nitrite, obtaining energy without requiring light (unlike photosynthetic organisms).

The saturation point is the CO2 concentration beyond which photosynthesis rate does not increase further, limited by other factors like temperature or light.

Power P = 1/f (in meters). P = $\frac{1}{0}$.15 = 6.67 Diopters (positive for converging lens)

The mirror equation relates object distance, image distance, and focal length to locate where an image forms in a concave mirror.

Step 1: [Identify Given Values]

For this concave mirror problem, we extract the known measurements from the question.

Step 2: [Apply Mirror Equation]

The mirror equation relates these three quantities and allows us to solve for the unknown image distance.

Substituting the values:

Since v is positive, the image forms in front of the mirror (on the same side as the object).

The image is formed 15 cm in front of the mirror. Answer: (B)

Using transformer equation Vs/Vp = Ns/Np, we get Vs = 220 × ($\frac{100}{500}$) = 44 V

The force on a current-carrying conductor in a magnetic field is called the Lorentz force, given by F = BIL

After 3 half-lives (30 years), the fraction remaining = ($\frac{1}{2}$)³ = $\frac{1}{8}$

In elastic collisions, both momentum and kinetic energy are conserved

Young's modulus Y = Stress/Strain = (F/A)/(ΔL/L), a measure of material stiffness

When object is between lens and focus (u < f), a convex lens produces virtual, erect, magnified image

First convert 72 km/h = 20 m/s. Using v = u + at: 0 = 20 + a(8), so a = -$\frac{20}{8}$ = -2.5 m/s². Magnitude of deceleration is 2.5 m/s².

Chlorine (Cl) has atomic number 17, with electronic configuration 2, 8, 7 (K-shell: 2, L-shell: 8, M-shell: 7).

Refractive index n = c/v. Therefore, v = c/n = (3 × 10⁸)/1.5 = 2 × 10⁸ m/s.

Elastic potential energy U = ½kx². U = ½ × 100 × (0.2)² = 50 × 0.04 = 2 J.

Insulin, produced by the pancreas, lowers blood glucose by facilitating glucose uptake into cells. Glucagon raises blood glucose levels.

Work by gravity W = -mgh (negative because displacement is opposite to force direction). W = -5 × 10 × 10 = -500 J.

For parallel connection: 1/R = $\frac{1}{6}$ + $\frac{1}{3}$ + $\frac{1}{2}$ = $\frac{1}{6}$ + $\frac{2}{6}$ + $\frac{3}{6}$ = $\frac{6}{6}$ = 1. Therefore R = 1Ω.