Physics Quiz: Effects Of Electric Current Trivia Questions!

Nichrome wire is used as the heating element because it has high specific resistance. Specific resistance refers to the resistance of a material per unit length and cross-sectional area. A material with high specific resistance will offer more resistance to the flow of electric current, causing it to heat up when a current is passed through it. This makes nichrome wire ideal for heating elements as it can withstand high temperatures without melting or deteriorating. Additionally, its high specific resistance allows for efficient conversion of electrical energy into heat.

The Peltier coefficient at a junction of a thermocouple depends on the temperature of the junction. This is because the Peltier effect, which is the phenomenon responsible for the generation or absorption of heat at the junction, is directly influenced by the temperature difference between the two ends of the thermocouple. The greater the temperature difference, the higher the Peltier coefficient and the more heat is generated or absorbed at the junction.

An ideal voltmeter is designed to measure voltage without drawing any current from the circuit being measured. In order to achieve this, it should have infinite resistance. This means that when connected in parallel with the circuit, the voltmeter will not create a parallel path for the current to flow through, ensuring accurate voltage measurement.

Joule's law of heating states that the heat produced in a conductor is directly proportional to the square of the current passing through it, the resistance of the conductor, and the time for which the current flows. This can be mathematically represented as Q = I^2 * R * t, where Q is the heat produced, I is the current, R is the resistance, and t is the time. Therefore, the correct answer is (3) because it accurately represents Joule's law of heating.

The effective resistance of the combination, Ra, is determined by the formula 1/Ra = 1/G + 1/S. Since both G and S are positive resistances, the sum of their reciprocals will always be greater than each individual resistance. Therefore, Ra must be less than both G and S.

The ammeter of range 0-10 A has a small resistance compared to the other devices listed. This is because an ammeter is designed to measure current, and in order to accurately measure the current flowing through a circuit, it needs to have a low resistance. A small resistance in the ammeter ensures that it does not significantly affect the current being measured, providing more accurate readings. The other devices listed, such as the ammeter of range 0-1 A, voltmeter, and moving coil galvanometer, may have higher resistances as they are designed for different purposes that do not require as low of a resistance.

The period of revolution of a charged particle inside a cyclotron does not depend on the velocity of the particle. This is because the magnetic field in a cyclotron is constant and perpendicular to the velocity of the particle. As a result, the magnetic force acting on the particle is always perpendicular to its velocity, causing it to move in a circular path. The radius of this circular path is determined by the magnetic field and the charge-to-mass ratio of the particle, but not its velocity. Therefore, the period of revolution remains constant regardless of the particle's velocity.

Phosphor-bronze wire is used for suspension in a moving coil galvanometer because it has a small couple per unit twist. This means that it requires less force to produce a given deflection in the wire, making it more sensitive to small current changes. Additionally, phosphor-bronze wire has high conductivity, which allows for efficient flow of current, ensuring accurate measurements. The other options, large couple per unit twist and high resistivity, would not be desirable for a galvanometer as they would either require excessive force or impede the flow of current.

The correct answer is (1) because in a thermocouple, the temperature of the cold junction is lower than the temperature of the hot junction. The neutral temperature is the temperature at which the thermoelectric voltage is zero, and it is usually between the temperatures of the hot and cold junctions. The temperature of inversion refers to the temperature at which the thermoelectric voltage changes sign, indicating a change in the direction of the thermoelectric current.

The torque on a rectangular coil placed in a uniform magnetic field is directly proportional to the number of turns in the coil. This means that as the number of turns increases, the torque also increases. This can be explained by the fact that each turn of the coil contributes to the overall magnetic moment, and a larger magnetic moment results in a larger torque. Therefore, when the number of turns is large, the torque on the coil is also large.

The Biot-Savart law is a fundamental equation in electromagnetism that describes the magnetic field produced by a steady current in a wire. The equation is given by (4), which states that the magnetic field at a point in space is directly proportional to the current flowing through the wire, the length of the wire segment, and the sine of the angle between the wire segment and the line connecting the point to the wire segment.

When the plane of the coil in a tangent galvanometer is rotated through 180 degrees, the deflection of the needle will be in the opposite direction. This is because the direction of the magnetic field produced by the coil will also change. Therefore, for the same current, the deflection will be in the opposite direction, which is represented by option (4).

The correct answer is (4) because an infinitely long straight conductor placed in a medium of permeability μ will result in magnetic induction. The permeability of the medium determines how easily magnetic fields can pass through it. In this case, the conductor will create a magnetic field around it due to the flow of electric current, and the permeability of the medium will determine the strength of this magnetic field. Therefore, the correct answer is (4) as it correctly identifies the magnetic induction caused by the conductor in the given scenario.