1.
In gases, the flow of current is due to?
Correct Answer
D. Electrons, positive ions and negative ions
Explanation
In gases, the flow of current is due to the presence of electrons, positive ions, and negative ions. Electrons are negatively charged particles that can move freely in a gas and carry electric current. Positive ions are atoms or molecules that have lost one or more electrons and carry a positive charge. Negative ions are atoms or molecules that have gained one or more electrons and carry a negative charge. The movement of these charged particles in a gas allows for the flow of electric current.
2.
The flow of current in solids is due to?
Correct Answer
A. Electrons
Explanation
The flow of current in solids is due to electrons. In solids, electrons are the charge carriers that move through the material when a voltage is applied. Electrons have a negative charge and are relatively free to move within the solid structure. They can be easily influenced by an electric field, allowing them to flow and carry the current. Ions, atoms, and the nucleus do not have the same mobility as electrons and therefore do not contribute significantly to the flow of current in solids.
3.
The minimum requirements for causing the flow of current are?
Correct Answer
B. A voltages source and a conductor
Explanation
The minimum requirements for causing the flow of current are a voltage source and a conductor. A voltage source provides the potential difference that drives the flow of electrons, while a conductor allows the electrons to move freely through it. Without a voltage source, there would be no potential difference to drive the flow of electrons, and without a conductor, the electrons would not have a pathway to flow through. Therefore, both a voltage source and a conductor are necessary for current to flow.
4.
Electric pressure is also called
Correct Answer
C. Voltage
Explanation
Voltage is the correct answer because electric pressure is commonly referred to as voltage. Voltage is the potential difference between two points in an electric circuit, which determines the rate at which electric energy is transferred. It is measured in volts and represents the force that pushes electric charges through a conductor.
5.
An instrument that detects electric current is known as?
Correct Answer
D. Galvanometer
Explanation
A galvanometer is an instrument that detects electric current. It is designed to measure and detect small electric currents. It works based on the principle of electromagnetic induction. When an electric current flows through a coil in the galvanometer, it produces a magnetic field. This magnetic field interacts with a permanent magnet or another coil, causing a deflection in a pointer or a needle. This deflection indicates the presence and strength of the electric current. Therefore, a galvanometer is the correct answer as it is specifically designed for detecting electric currents.
6.
Which of the following ampere-second could be the unit?
Correct Answer
B. Charge
Explanation
The unit "ampere-second" is commonly used to measure electric charge. It is a combination of the unit of current (ampere) and the unit of time (second). Charge is a fundamental property of matter and is measured in units of coulombs (C). The product of current and time, which is measured in ampere-seconds, represents the amount of charge that has passed through a point in a circuit. Therefore, ampere-second is a valid unit for measuring charge.
7.
The rating of the fuse wire is always expressed in?
Correct Answer
D. Ampere
Explanation
The rating of the fuse wire is always expressed in amperes because it indicates the maximum current that the fuse can safely handle before it blows and interrupts the circuit. Ampere is the unit of measurement for electric current, making it the appropriate unit for expressing the rating of a fuse wire. Ampere-hours, ampere-volts, and KWH are not suitable units for expressing the rating of a fuse wire as they represent different measurements related to energy and power.
8.
The S.I. unit of power is?
Correct Answer
C. Watt
Explanation
The S.I. unit of power is watt. Power is defined as the rate at which work is done or energy is transferred. The watt is a derived unit of power in the International System of Units (SI), named after the Scottish engineer James Watt. It is equivalent to one joule of work or energy per second. The watt is widely used in physics, engineering, and everyday life to measure the power consumption of devices and the rate at which energy is generated or consumed.
9.
The temperature coefficient of resistance is expressed in terms of?
Correct Answer
C. Ohms/ohmoC
Explanation
The temperature coefficient of resistance is a measure of how much the resistance of a material changes with temperature. It is expressed in units of ohms per degree Celsius (Ω/°C). This indicates the change in resistance for every degree Celsius change in temperature. The correct answer, "Ohms/ohmoC," is a typographical error and should be "Ohms/°C."
10.
One newton meter is the same as?
Correct Answer
B. 1 joule
Explanation
One newton meter is the same as 1 joule. This is because both newton meters and joules are units of energy. A newton meter is the amount of energy required to move an object with a force of one newton over a distance of one meter. Similarly, a joule is also a unit of energy and is defined as the amount of work done when a force of one newton is applied over a distance of one meter. Therefore, one newton meter is equal to one joule.