Description : What happens to insulation when temperature rises?
Last Answer : For insulators, an increase in temperature will cause their resistance to decrease -which is why excessive temperature is often the main reason why insulation fails
Description : The force between two long parallel conductors is inversely proportional to (a) radius of conductors (b) current in one conductor (c) product of current in two conductors (d) distance between the conductors
Last Answer : (d) distance between the conductors
Description : The two conductors of a transmission line carry equal current I in opposite directions. The force on each conductor is (a) proportional to 7 (b) proportional to X (c) proportional to distance between the conductors (d) inversely proportional to I
Last Answer : (b) proportional to X
Description : Asingle fiber can handle asmanyvoice channel as a. a pair of copper conductors b. a1500-pair cable c. a 500-pair cable d. a 1000-pair cable
Last Answer : b. a1500-pair cable
Description : Current carried by each of the two long parallel conductors is doubled. If their separation is also doubled , force between them is
Last Answer : Increase two fold
Description : Good conductors have conductivity of the order of a) 10–10 (m)–1 b) 10–7 (m)–1 c) 10 7 (m)–1 d) 10–9 (m)–1
Last Answer : c) 10 7 (m)–1
Description : Substances of conductivity between 10–10 10–20 (n m )–1 are: a) Insulators b) Semiconductors c)Super conductors d)Good conductors
Last Answer : a) Insulators
Description : he substances of conductivity of the order of 10–6 – 10–4 (m)–1 are : a) Insulators b) Super conductors c) Semiconductors d)Good conductors
Last Answer : d)Good conductors
Description : Metals are good conductors of electricity because they have: (a) Large number of bounded electrons (b) Small number of electrons (c) Large number of free electrons (d) Small number of free electrons
Last Answer : (c) Large number of free electrons
Description : Which of the following statement is correct: (a) Similar charges attract each other (b) Similar charges attract and repel each other (c) Similar charges repel each other (d) Similar charges neither attract nor repel 9. Metals are good conductors of electricity because they have:
Last Answer : (c) Similar charges repel each other
Description : The fractional change in resistance per kelvin is known as, a. temperature coefficient of resistance b. coefficient of Voltage of charge c. thermal expansion d. all of above
Last Answer : a. temperature coefficient of resistance
Description : Resistance of a wire on increasing its temperature will a. increase with rise in temperature b. decrease with rise in temperature c. will remain same d. depends upon altitude of experimentation
Last Answer : a. increase with rise in temperature
Description : Anincidentraycan be defined as a. a light ray reflected from a flat surface b. alight raydirectedtowardasurface c. a diffused light ray d. a light ray that happens periodically
Last Answer : b. alight raydirectedtowardasurface
Description : Explain what happens if a DC motor is fed with AC supply
Last Answer : Motor will run at low speed, sparking at brushes, heat due to eddy current will finally burn the motor.
Description : If PN junction is forward biased its resistance is (a) Zero (b) Infinity (c) A few ohm (d) A few kilo ohms
Last Answer : c) A few ohm
Description : The emitter of a transistor is doped the heaviest because it: (a) Acts as a supplier of charge carriers (b) Dissipates maximum power c) has a large resistance (d) has a small resistance
Last Answer : (a) Acts as a supplier of charge carriers
Description : The operational amplifier is _______ (a) High gain amplifier (b) high power amplifier (c)high resistance amplifier (d)low resistance amplifier
Last Answer : a) High gain amplifier
Description : The induced emf in a coil depends upon: a. Strength of magnetic field b. Resistance of the coil c. area of the coil d. All of them
Last Answer : d. All of them
Description : The current flowing in a coil due to induced emf depends upon: a. shape of coil b. resistance of coil c. area of coil d. magnetic flux
Last Answer : a. shape of coil
Description : A galvanometer having a resistance of 4.5 Ω can read up to 5 mA. If it is to read 100 V, then the high resistance to be used in series will be a) 19998 Ω b) 19995.8 Ω c) 19995.5 Ω d) 19996.5 Ω
Last Answer : c) 19995.5
Description : A galvanometer has resistance of 120 Ω. In order to pass 5% of the main current in it, the value of shunt resistance Rs must be equal to a) 6.3 Ω b) 6 Ω c) 2 Ω d) 2.3 Ω
Last Answer : a) 6.3 Ω
Description : A galvanometer of 65 Ω resistance gives full scale deflection with 4 mA current. In order to convert it into ammeter, the range of 10 A is connected with it, the shunt resistance should be a) 0.1 Ω b) 0.2 Ω c) 0.06 Ω d) 0.03 Ω
Last Answer : d) 0.03 Ω
Description : A multipurpose instrument for measuring current, potential difference and resistance is a) Ohmmeter b) Astatic galvanometer c) Rheostat d) AVO Meter
Last Answer : d) AVO Meter
Description : Shunt resistance Rs is given as a) Ig I−Ig Rg b) Ig I+Ig Rg c) I I−Ig Rg d) None of these
Last Answer : a) Ig I−Ig Rg
Description : Desirable resistance of a ________ is achieved by connecting a high resistance Rh in series with a galvanometer a) Ammeter b) Ohmmeter c) LED d) Voltmeter
Last Answer : d) Voltmeter
Description : When the potential difference of 4 volt is applied across resistance, 10J energy is converted. Find the charge flows. a. 0.20 C b. 2.5C c. 5C d. 10C
Last Answer : b. 2.5C
Description : Three resistors of resistance R are connected in various ways, which of the following cannot be obtained? a. 3R ohm b. 2R/4 ohm c. R/3 ohm d. 2R/3 ohm
Last Answer : b. 2R/4 ohm
Description : Terminal potential difference of a battery is greater than its emf when a. the internal resistance of battery is infinite b. the internal resistance of battery is zero c. the battery is charged d. the battery is discharged
Last Answer : c. the battery is charged
Description : Which one of the following bulbs has the least resistance? a. 100 watt b. 200 watt c. 300 watt d. 60 watt
Last Answer : c. 300 wat
Description : Why should a resistance be introduced in a circuit in series deliberately? a. to increase current b. to decrease current c. to control current d. just to give a good look to circuit
Last Answer : b. to decrease current
Description : The resistance of a conductor at absolute zero (OK) is a. zero almost b. infinite almost c. May increase or decrease d. None
Last Answer : zero almost
Description : Specific resistance of a wire a. will depend on its length b. will depend on its radius c. will depend on the type of material of the wire d. will depend on none of the above
Last Answer : c. will depend on the type of material of the wire
Description : A neon flashlight cell with an emf of 1.5V gives a current of 15A when connected directly to an ammeter of resistance 0.04?. Internal resistance of the cell is a. 0.0004? b. 0.06? c. 0.10? d. 0.13?
Last Answer : b. 0.06?
Description : Resistance between points A and B in the circuit shown in figure is a. 4 ohm b. 6ohm c. 10 ohm d. 8 ohm
Last Answer : c. 10 ohm
Description : Internal resistance is the resistance offered by a. source of e m f b. Conductor c. Resistor d. Capacitor
Last Answer : a. source of e m f
Description : When 2,4 and 6 ohms resistor are connected in parallel their resultant equivalent resistance will be A. 12ohm b. 11/12ohm C. 12/11ohm d. None
Last Answer : C. 12/11ohm
Description : Resistance of an ideal insulator is a. Infinite b. Zero c. Finite d. depends upon nature
Last Answer : a. Infinite
Description : A wire of uniform area of cross-section A length L and resistance R is cut into two parts. Resistivity of each part a. remains the same b. is doubled c. is halved d. becomes zero
Last Answer : a. remains the same
Description : The resistance of a few meters of wire conductor in closed electrical circuit is?
Last Answer : The resistance of a few meters of wire conductor in closed electrical circuit is practically zero.
Description : When an alternating current passes through an ohmic resistance the electrical power converted into heat is?
Last Answer : When an alternating current passes through an ohmic resistance the electrical power converted into heat is true power.
Description : What happens when a objects temperature rises?
Last Answer : The molecules which make up the objects move morevigorously.
Description : On a day when the partial pressure of water vapor remains constant, what happens as the temperature rises? a. the relative humidity increases b. the relative humidity decreases c. the relative humidity remains constant d. the air would eventually become saturated
Last Answer : the relative humidity decreases
Description : When temperature rises, resistance of negative temperature coefficient thermistor A. increases B. decreases C. zero D. infinity
Last Answer : decreases
Description : Super conductors are substances that – (1) offer minimum resistance to flow of electric current (2) conduct electricity at low temperature (3) conduct electricity at high temperature (4) offer high resistance to the flow of electric current
Last Answer : (1) offer minimum resistance to flow of electric current Explanation: A superconductor is a material that can conduct electricity or transport electrons from one atom to another with no ... is released from the material when it reaches the temperature at which it becomes superconductive.
Description : Certain substances loose their electrical resistance completely at super low temperature. Such, substances are called. (1) Super conductors (2) Semi conductors (3) Dielectrics (4) Perfect conductors
Last Answer : (1) Super conductors Explanation: Superconductors are materials that carry electrical current with little or no resistance when cooled, below a certain temperature. While conventional superconductors need to ... temperature superconductors do so above the boiling point of liquid nitrogen (-196 °C).
Description : Super conductors are those substances, which (A) Offer no resistance to current flow (B) Conduct electricity at low temperature (C) Offer high resistance to current flow (D) Conduct electricity at high temperature
Last Answer : (A) Offer no resistance to current flow
Description : Semi-conductors have ________ temperature coefficient of resistance. (A) Negative (B) Positive (C) Both positive and negative (D) None of the above
Last Answer : (A) Negative
Description : Super conductors are substances that (1) offer minimum resistance to flow of electric current (2) conduct electricity at low temperature (3) conduct electricity at high temperature (4) offer high resistance to the flow of electric current
Last Answer : offer minimum resistance to flow of electric current
Description : Certain substances loose their electrical resistance completely at super low temperature. Such substances are called. (1) Super conductors (2) Semi conductors (3) Dielectrics (4) Perfect conductors
Last Answer : Super conductors
Description : With rise in temperature the resistance of semi-conductors?
Last Answer : With rise in temperature the resistance of semi-conductors decreases.