1.
Which of the following is a non metal that remains liquid at room temperature?
Correct Answer
B. Bromine
Explanation
Bromine is a non-metal that remains liquid at room temperature. It is the only non-metal element that exists in a liquid state at normal room temperature and pressure. Phosphorous is a solid, chlorine is a gas, and helium is also a gas at room temperature. Therefore, the correct answer is bromine.
2.
A car traveling at 50 km/hr changes its speed to 110 km/hr is 5 seconds. The acceleration of the car during this time is
Correct Answer
B. 12 km/hr/sec
Explanation
The acceleration of the car can be calculated using the formula:
acceleration = (final velocity - initial velocity) / time
In this case, the initial velocity is 50 km/hr, the final velocity is 110 km/hr, and the time is 5 seconds.
Substituting these values into the formula, we get:
acceleration = (110 km/hr - 50 km/hr) / 5 seconds
acceleration = 60 km/hr / 5 seconds
acceleration = 12 km/hr/sec
Therefore, the correct answer is 12 km/hr/sec.
3.
_________ is the biggest planet in our solar system.
Correct Answer
jupitar
Explanation
Jupiter is the largest planet in our solar system. It is a gas giant and has a diameter of about 143,000 kilometers, which is more than 11 times the diameter of Earth. Jupiter also has the highest mass among all the planets, accounting for more than twice the combined mass of all the other planets in the solar system. Its size and mass make Jupiter a dominant force in shaping the dynamics of the solar system.
4.
Who was awarded the 1921 Nobel Prize in Physics for his work on theoretical physics?
Correct Answer
B. Elbert Einstien
Explanation
Albert Einstein was awarded the 1921 Nobel Prize in Physics for his work on theoretical physics, specifically for his discovery of the law of the photoelectric effect. His contributions to the field revolutionized our understanding of light and laid the foundation for the development of quantum mechanics.
5.
A vector quantity has
Correct Answer
A. Magnitude only
Explanation
A vector quantity has both magnitude and direction. This means that it not only has a numerical value (magnitude) but also a specific orientation or position in space (direction). Examples of vector quantities include velocity, force, and displacement.
6.
DNA is the shortened form of the term ‘Deoxyribonucleic acid’?
Correct Answer
A. True
Explanation
DNA is indeed the shortened form of the term "Deoxyribonucleic acid." DNA is a molecule that carries genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses. It is composed of two long chains of nucleotides twisted into a double helix structure. The abbreviation "DNA" is commonly used to refer to this molecule in scientific and everyday contexts. Therefore, the statement "DNA is the shortened form of the term 'Deoxyribonucleic acid'" is true.
7.
The sum of all the external forces on a system of particles is zero. Which of the following must be true of the system?
Correct Answer
D. The total linear momentum is constant.
Explanation
When the sum of all the external forces on a system of particles is zero, it means that there is no net external force acting on the system. According to Newton's second law, the rate of change of momentum of an object is equal to the net external force acting on it. Therefore, if there is no net external force, the total linear momentum of the system will remain constant. This means that the total linear momentum of the system will not change over time.
8.
The two elements that are frequently used for making transistors are
Correct Answer
B. Silicon and Germanium
Explanation
Silicon and Germanium are frequently used for making transistors because they are both semiconductor materials. Transistors are electronic devices that control the flow of electrical current in a circuit. Semiconductors have the unique property of being able to conduct electricity under certain conditions and act as insulators under others. Silicon and Germanium have a similar crystal structure which allows them to easily form the necessary p-n junctions required for transistor operation. Additionally, these materials have desirable electrical properties such as high carrier mobility and stability, making them ideal for use in transistors.
9.
Reading of a barometer going down is an indication of
Correct Answer
D. Rainfall
Explanation
A barometer measures atmospheric pressure, and a decrease in the barometer reading indicates a decrease in air pressure. This decrease in pressure is often associated with the approach of a weather system, such as a low-pressure system, which typically brings rainfall. Therefore, a barometer reading going down is an indication of rainfall.
10.
Which of the following is a non metal that remains liquid at room temperature?
Correct Answer
B. Bromine
Explanation
Bromine is a non metal that remains liquid at room temperature. It is the only option among the given choices that is a non metal and exists in a liquid state at normal room temperature. Phosphorous is a solid, chlorine is a gas, and helium is also a gas at room temperature.