Explanation

In the story (likely referring to a war-time or storm-related narrative).

It is Ellen who suggests going to the cellar, likely as a place of safety or shelter.

This reflects her awareness of danger and desire to protect others.

Explanation

The total resistance (R) in the series circuit is:

R = 5 + 10 + 10

= 25 Ω

The current (I) is given by Ohm's law:

I = V/R

= 50V / 25Ω

= 2A

Explanation

Apparent weight = Normal force, and when moving upward with acceleration g, total acceleration = g + g = 2g.

So, Apparent weight = m × (g + g) = 2mg.

Explanation

Nitrogen makes up about 3% of the human body by mass.

It is mostly found in proteins, DNA, and RNA.

It is essential for building amino acids and nucleic acids in the body.

Explanation

The phrase “placed on the table” means the book is resting directly on the surface.

"On" correctly shows contact between the book and the table.

Explanation

Sodium (Na) and Chlorine (Cl) together make up about 0.45% of the human body mass.

They are essential electrolytes that help regulate fluid balance, nerve function, and muscle activity.

Explanation

A commutator is used in DC motors and generators to reverse or maintain the direction of current correctly.

It ensures that the current flows in one direction through the external circuit.

Explanation

Starch is a type of polysaccharide, which falls under the category of carbohydrates.

It is a complex carbohydrate made up of many glucose units and serves as an energy storage molecule in plants.

Explanation

When hydrogen loses its electron, it forms H⁺, similar to alkali metals (like Na⁺, K⁺) that also form +1 ions.

Due to this behavior, hydrogen is often placed in Group 1 (alkali metals) in the periodic table.

Explanation

sp² hybridization involves one s and two p orbitals, forming three hybrid orbitals in a planar triangular (trigonal planar) shape.

The bond angles in this geometry are approximately 120°, seen in molecules like BF₃ or C₂H₄.