Front

What is heat?

Back

A form of energy transferred due to temperature difference.

Answer explanation

Heat is defined as a form of energy that is transferred between systems due to a temperature difference. This distinguishes it from motion, time, or chemical reactions, making the second choice the correct answer.

Front

Freezing point of water in Celsius?

Back

0°C

Answer explanation

The freezing point of water is 0°C. This is the temperature at which water transitions from liquid to solid. The other options represent different temperature scales or points, but 0°C is the correct answer.

Front

Method of heat transfer involving direct contact?

Back

Conduction

Answer explanation

Conduction is the method of heat transfer that occurs through direct contact between materials. In this process, heat moves from the hotter object to the cooler one through molecular collisions.

Front

First law of motion states:

Back

An object at rest stays at rest.

Answer explanation

The first law of motion, also known as Newton's first law, states that an object at rest stays at rest unless acted upon by a net external force. This highlights the concept of inertia.

Front

Unit of electric current?

Back

Amperes

Answer explanation

The unit of electric current is measured in Amperes, often abbreviated as 'A'. Other options like Watts, Volts, and Ohms refer to power, voltage, and resistance, respectively, and are not units of current.

Front

Type of current that flows in one direction.

Back

Direct Current

Answer explanation

Direct Current (DC) flows in one direction, unlike Alternating Current (AC), which reverses direction periodically. Static Current and Magnetic Current are not standard terms for electrical current.

Front

Speed of light in a vacuum?

Back

299,792,458 m/s

Answer explanation

The speed of light in a vacuum is precisely 299,792,458 meters per second. This value is a fundamental constant in physics, making it the correct choice among the options provided.

Front

Acids and blue litmus paper?

Back

Turn it red.

Answer explanation

Acids change blue litmus paper to red due to the presence of hydrogen ions, which indicate acidity. This color change is a standard test for identifying acidic substances.

Front

Produced in a neutralization reaction?

Back

Salt and water

Answer explanation

In a neutralization reaction, an acid reacts with a base to produce salt and water. This is a fundamental concept in chemistry, making 'salt and water' the correct answer.

Front

pH range for basic substances?

Back

7-14

Answer explanation

Basic substances have a pH greater than 7, indicating they are alkaline. The pH scale ranges from 0 to 14, so the correct range for basic substances is 7-14.