PHYSICS
FOR SEMI CONDUCTOR TO HAVE NEGATIVE TEMPERATURE COEFFICIENT OF RESISTANCE IMPLIES THAT
A. their resistance decrease with temperature ✓ B. The resistance increase with temperature C. their resistance is constantly changing with temperature D. they have electrons and holes at high temperature In semiconductors, the temperature coefficient of resistance (TCR) indicates how the resistance…
A GENERATOR MANUFACTURING COMPANY WAS CONTRACTED TO PRODUCE AN A.C DYNAMO BUT INADVERTENTLY PRODUCED A D.C DYNAMO. TO CORRECT THIS ERROR, THE
A. armature coil should be made of silver B. commutator should be replaced with slip ring ✓ C. commutator should be replaced with split rings D. armature coil should be made of aluminium The scenario presented involves a generator manufacturing company that…
IF THE SIZE OF THE HOLE OF A PINHOLE CAMERA IS INCREASED, THE IMAGE FORMED BECOMES
A. brighter and blurred B. brighter and larger C. brighter and sharper D. blurred and duller E. blurred and larger ✓ A pinhole camera works by allowing light to pass through a small aperture or hole, forming an inverted image on the opposite…
IN AN OPERATING X-RAY TUBE, A HIGH P.D IS APPLIED BETWEEN THE CATHODE AND THE ANODE FOR THE PURPOSE OF
A. accelerating the electrons to a very high energy ✓ B. concentrating electrons on the target C. heating the anode D. heating the cathode E. producing a stream of electrons An X-ray tube is a device used in medical imaging and industrial applications…
THE RESULTANT FORCE IN A COUPLE IS
A. zero ✓ B. infinite C. the sum of the forces D. thr product of the forces Explanation: Couple Definition: A couple is a pair of forces that are equal in magnitude, opposite in direction, and do not share the same line…
MATERIALS THAT CAN BE STRETCHED AND STILL RETURN TO THEIR ORIGINAL FORMS WHEN THE STRESSES ARE REMOVED ARE SAID TO BE
A. elastic ✓ B. elastomer C. plastic D. thermoplastic When materials can be stretched and still return to their original form when the stresses are removed, they are said to be elastic. Elasticity is the property of a material that allows it to…
WHICH PROPERTY OF A WAVE REMAINS CONSTANT WHEN THE WAVE TRAVELS FROM ONE MEDIUM INTO ANOTHER
A. Amplitude B. Wavelength C. Velocity D. Frequency ✓ When a wave travels from one medium into another, the property that remains constant is the frequency. Frequency is defined as the number of complete oscillations or cycles of a wave that occur…
A FRESHLY DEMAGNETIZED BAR MAGNET IS PLACED IN THE EAST-WEST DIRECTION TO ENSURE THAT
A. the molecular magnets remain randomly arranged ✓ B. the molecular magnets are properly aligned C. it is affected by the earth’s magnetic field D. the magnetic domains are within the earth’s field In this scenario, when a freshly demagnetized bar magnet…
A HEAT SENSITIVE RESISTOR MADE OF A SEMICONDUCTOR IS CALLED
A. thermometer B. thermostat C. thermistor ✓ D. thermopile Thermistors are electronic components that exhibit a large change in resistance with a small change in temperature. They are commonly used in various applications such as temperature sensing, temperature compensation,…
THE REASON FOR LAMINATING THE SOFT IRON CORE OF A TRANSFORMER IS TO
A. reduce eddy current ✓ B. reduce magnetic flux C. increase the magnetic flux D. reduce its efficiency The reason for laminating the soft iron core of a transformer is to reduce eddy currents. Laminating the core involves insulating…
A STONE OF MASS 1KG IS DROPPED FROM A HEIGHT OF 10M ABOVE THE GROUND AND FALLS FREELY UNDER GRAVITY. ITS KINETIC ENERGY 5M ABOVE THE GROUND IS THEN EQUAL TO
A. its kinetic energy on the ground B. twice its initial potential energy C. its initial potential energy D. half its initial potential energy ✓ When the stone is dropped from a height of 10m above the ground, it possesses gravitational potential…
A CERTAIN RADIOACTIVE SOURCE EMITS RADIATIONS THAT WERE FOUND TO BE DEFLECTED BY BOTH MAGNETIC AND ELECTRIC FIELDS. THE RADIATIONS ARE
A. beta rays ✓ B. gamma rays C. x-rays D. ultraviolet rays The radiations that are deflected by both magnetic and electric fields are beta rays. Beta rays are high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei…
A RADIO IS OPERATED BY EIGHT CELLS EACH OF E.M.F. 2.0V CONNECTED IN SERIES. IF TWO OF THE CELLS ARE WRONGLY CONNECTED, THE NET E.M.F. OF THE RADIO IS
A. 8V B. 10V C. 12V ✓ D. 16V When eight cells each with an electromotive force (e.m.f.) of 2.0V are connected in series to operate a radio, the total e.m.f. of the system is calculated by adding up the individual e.m.f.…
A GAS WOULD SERVE AS AN ELECTRICAL CONDUCTOR UNDER
A. reduced pressure and high current ✓ B. increased magnetic field C. reduced pressure and reduced potential D. exposure to visible light When the pressure of a gas is reduced, the distance between gas molecules increases, allowing for easier movement of charged…
IF A CHARGED ION GOES THROUGH COMBINED ELECTRIC AND MAGNETIC FIELDS, THE RESULTANT EMERGENT VELOCITY OF THE ION IS
A. E/B ✓ B. EB C. B/E D. E – B When a charged ion moves through combined electric and magnetic fields, the resultant emergent velocity of the ion can be calculated using the Lorentz force equation. The Lorentz force is the…
THE INNER DIAMETER OF A TEST TUBE CAN BE MEASURED ACCURATELY USING A
A. micrometer screw gauge B. pair of dividers C. metre rule D. pair of vernier calipers ✓ Vernier calipers are precise measuring instruments that are commonly used to measure the inner diameter of objects, such as the inside of a test…
THE PROPERTY OF A BODY TO REMAIN AT REST OR TO CONTINUE IN UNIFORM MOTION IN A STRAIGHT LINE IS CALLED
A. momentum B. Inertia ✓ C. impulse D. Energy This concept is one of the fundamental laws of physics, described by Sir Isaac Newton in his first law of motion, also known as the “law of inertia.” Inertia is a measure of…
ELECTRIC CHARGES ON THE SURFACE OF A CONDUCTOR WOULD BE MOST EVENLY DISTRIBUTED IF THE SHAPE OF THE CONDUCTOR IS
A. conical B. cubical C. cylindrical D. parabolic E. spherical ✓ Electric charges on the surface of a conductor would be most evenly distributed if the shape of the conductor is spherical. This is due to the property of conductors known as electrostatic…
