Which of the following types of thermometer is used for the calibration of other thermometers?

• A. liqud-in-glass thermometer
• B. constant volume gas thermometer
• C. optical pyrometer
• D. thermocouple

An electric pressing iron is connected to the mains using an insulated wire. wire becomes very hot.

The heat generated in the wire can be minimized by replacing the wire with one of?

• A. thinner insulation.
• B. greater diameter.
• C. smaller diameter.
• D. thicker insulation.

Two charged particles are projected into a region where there is a magnetic field perpendicular to their velocities. if the charges are deflected in opposite directions, which of the following statements is true of the charge?

• A. the charge must be of opposite sign
• B. positive charges are more in number
• C. the charges are electrically neutral
• D. the charges are of the same sign

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce temperature increase because

• A. all the heat is used to break the bonds holding the molecules of the solid together
• B. the heat capacity has become very large as the substance melts
• C. the heat energy is quickly conducted away
• D. the heat gained is equal to the heat lost by the substance

The temperature gradient across a copper rod of thickness 0.02m, maintained at two temperature junctions of 20º and 80ºC respectively is?

• A. 3.0 x 10²km^-1
• B. 3.0 x 10³km^-1
• C. 5.0 x 10³km^-1
• D. 3.0 x 10⁴km^-1

Cathode rays are

• A. High-energy electromagnetic waves
• B. protons
• C. neutrons
• D. streams of electrons

The device in which one circuit controls another, especially if the current in the second circuit is large or dangerous is known as

• A. Electromagnetic devices
• B. Magnetic relay device
• C. None at all
• D. Sextant

(i) What is dielectric?

(ii) A parallel plate capacitor consists of two plates each of area 9.6 x 10\(^{-2}\)m\(^2\), separated by a dielectric of thickness 2.25 x 10\(^{-3}\) and dielectric constant 900. Calculate the capacitance of the capacitor. [ \(\varepsilon_o\) = permittivity of free space = 8.85 x 10\(^{-12}\)Fm\(^{-1}\)]

(b) (i) Which of the following devices has a higher resistance; an ammeter or a voltmeter? Give a reason for your answer.

(ii)

The resistance of the voltmeter in the circuit diagram illustrated above is 800\(\Omega\), Calculate the voltmeter reading.

(c)

A battery of negligible internal resistance is connected to a set of resistors as illustrated in the circuit diagram below. Determine the equivalent resistance of the circuit.

The current in a reverse-biased junction is due to?

• A. minority carriers
• B. electrons
• C. majority carriers
• D. holes

Red light travels faster than blue light when both of them pass through a glass prism because the

• A. refractive index of red light is grester than that of blue light
• B. refractive index of blue light is greater than that of red light
• C. red light is more intense than the blue light
• D. blue light is more intense than the red light