A galvanometer is used to measure the voltage of a cell by connecting a/an ______ with it.

Here are the solutions to the questions:

12. A galvanometer is used to measure the voltage of a cell by connecting a/an ______ with it.
To convert a galvanometer into a voltmeter, a high resistance is connected in series with the galvanometer. This modified device (voltmeter) is then connected in parallel across the cell to measure its voltage. The question asks how a galvanometer is used to measure voltage, implying its modification.
The correct option is E. wire of high resistance in series

13. Kerosene rises up the wick of a lamp due to.
The phenomenon of a liquid rising in a narrow tube or porous material (like a lamp wick) is called capillary action. This action is a result of the combined effects of adhesion (attraction between liquid and solid), cohesion (attraction between liquid molecules), and surface tension.
The correct option is E. cohesion, surface tension and adhesion.

14. When an electron is completely removed from an atom, the atom becomes.
An atom is electrically neutral, having an equal number of protons (positive charge) and electrons (negative charge). When an electron is removed, the atom loses a negative charge, resulting in a net positive charge. An atom with a net electrical charge is called an ion.
The correct option is C. ionized.

15. During electroplating, the material to be deposited is made the.
In electroplating, the object onto which a layer of metal is to be deposited is connected as the cathode (negative electrode) in an electrolytic cell. Metal ions from the electrolyte are reduced and deposited onto the cathode.
The correct option is B. cathode.

16. Which of the statements below is not correct about a machine? It is a device which.
Machines are designed to make work easier by changing the magnitude or direction of force, or by changing the distance over which the force acts. They can decrease the force applied, enable work to be done easily, reduce time, and use little effort for a large load. While machines do require maintenance, this is a practical aspect of their use, not a fundamental characteristic of how they function to modify work.
The correct option is D. requires maintenance.

17. Kainji dam is mainly used for.
Kainji Dam is a major hydroelectric dam located in Nigeria. Its primary purpose is the generation of electricity through hydropower.
The correct option is C. power generation.

18. Which of the following is a component of a rocket?
A rocket is a complex vehicle with many components.

• A. Antenna: Used for communication and telemetry.
• B. Gyroscope: Essential for the guidance and control system.
• C. Nose cone: The aerodynamic front part of a rocket that protects the payload.
• D. Solar panel: Typically used to power the payload (e.g., a satellite or spacecraft) once in space, not usually the rocket stages themselves.
• E. Star tracker: Used for precise navigation and attitude determination, primarily for the payload or spacecraft. While A, B, and C are all valid components of a rocket, the nose cone is a very distinct and fundamental structural component. The correct option is C. Nose cone

19. Rocket and artificial satellite are used for.
Rockets are primarily used to launch artificial satellites into orbit. Artificial satellites serve a wide range of purposes. Many satellites, such as communication satellites, navigation satellites (like GPS), and weather satellites, are fundamentally involved in transmitting various types of signals (e.g., voice, data, navigation signals, weather imagery).
The correct option is D. transmitting signal.