Description : A copper wire of length l and diameter d has potential difference V applied at its two ends. The drift velocity is vd . If the diameter of wire is made d/3, then drift velocity becomes
Last Answer : A copper wire of length l and diameter d has potential difference V applied at its two ends. The drift velocity is vd . If the diameter of wire is made d/3, then drift velocity becomes vd.
Description : The free electrons of a copper wire of cross-sectional area `10^(-6) m^(2)` acquire a drift velocity of `10^(-4) m//s` when a certain potential differ
Last Answer : The free electrons of a copper wire of cross-sectional area `10^(-6) m^(2)` acquire a drift velocity of `10 ... is `8.5xx10^(28) "electrons"//m^(3)`.
Description : Barrier potential in a P-N junction is caused by (A) Thermally generated electrons and holes. (B) Diffusion of majority carriers across the junction. (C) Migration of minority carriers across the junction. (D) Flow of drift current.
Last Answer : (B) Diffusion of majority carriers across the junction.
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 : A straight wire of length 0.20 m moves at a steady speed of 3.0 m s-1 at right angles to the magnetic field of flux density 0.10 T. The e.m.f induced across ends of wire is A. 0.5 V B. 0.06 V C. 0.05 V D. 0.04 V
Last Answer : 0.06 V
Description : A potential difference of 10 V is applied across a conductor of resistance `1 k Omega`. Find the number of electrons flowing through the conductor in
Last Answer : A potential difference of 10 V is applied across a conductor of resistance `1 k Omega`. ... of electrons flowing through the conductor in 5 minutes.
Description : Calculate the drift velocity for the electrons in a silver wire which has a radius of 0.1 cm and carries a current of 2 A. Atomic mass of silver=108 a
Last Answer : Calculate the drift velocity for the electrons in a silver wire which has a radius of 0.1 cm and carries a ... silver `=10.5xx10^(3) kg//m^(3)`.
Description : Mean drift velocity of electron in a copper wire having cross-sectional area 5.0 × 10-6 m2 carrying current of 1 A and having number density 8.5 × 1028 m3 is A. 0.015 mm s-1 B. 0.1 mm s-1 C. 0.5 mm s-1 D. 0.25 mm s-1
Last Answer : 0.015 mm s-1
Description : What is the drift velocity of electrons in a copper conductor having a cross-sectional area of `5xx10^(-6) m^(2)` if the current is 10 A. Assume there
Last Answer : What is the drift velocity of electrons in a copper conductor having a cross-sectional area of `5xx10^(-6) m^( ... `8.0xx10^(28) "electrons"//m^(3)`.
Description : A shaft of length l carries two discs at its two ends. The lowest torsional frequency is ω n . If the shaft length is doubled, then the lowest torsional frequency becomes A ω n /2 B ω n /√2 C √2ω n D 2ω n
Last Answer : B ω n /√2
Description : A solenoid has n turns and length l. If length is reduced to l/2 and turns are doubled then magnetic field B produced by it becomes equal to a) 2B b) 4B c) 1/2 B d) None of these
Last Answer : a) 2B
Description : A copper wire 4 mm in diameter is evenly wound about a cylinder whose length is 24 cm and diameter 20 cm so as to cover the surface. -Maths 9th
Last Answer : answer:
Description : Assertion : If a current is flowing through a conducting wire of non-uniform cross-section, drift speed and resistance both will increase at a section
Last Answer : Assertion : If a current is flowing through a conducting wire of non-uniform cross-section, drift ... . If Assertion is false but Reason is true.
Description : In the figure shown, a conducting wire PQ of length l=1m, is moved in a uniform magnetic field B=4T with constant velocity v=2m/s towards right. Given
Last Answer : In the figure shown, a conducting wire PQ of length l=1m, is moved in a uniform magnetic field B=4T with ... P_(2) = 32 J//s` D. None of these
Last Answer : In the figure shown, a conducting wire PQ of length l=1m, is moved in a uniform magnetic field B=4T with constant ... `16 N` C. `24 N` D. `32 N`
Last Answer : In the figure shown, a conducting wire PQ of length l=1m, is moved in a uniform magnetic field B=4T with constant ... `0` B. `2A` C. `4A` D. `6A`
Description : Potentiometer wire of length `1 m` is connected in series with `490 Omega` resistance and `2 V` battery. If `0.2 mV/cm` is the potential gradient, the
Last Answer : Potentiometer wire of length `1 m` is connected in series with `490 Omega` resistance and `2 V` battery. If ... 7.9Omega` C. `5.9Omega` D. `6.9Omega`
Description : A metal wire of circular cross-section has a resistance `R_(1)`. The wire is now stretched without breaking, so that its length is doubled and the den
Last Answer : A metal wire of circular cross-section has a resistance `R_(1)`. The wire is now stretched without breaking, so that its ... 2` C. `4 : 1` D. `1 : 4`
Description : If the length of a wire is halved and the cross-sectional area is doubled, the resistance will be _____________. A. quartered B. unchanged C. doubled D. quadrupled
Last Answer : Answer: A
Description : What happens to the resistance of a wire when its length as well as the cross-sectional area are doubled? A) It doubles B) It becomes 4 times C) It becomes 2π times D) It remains the same
Last Answer : Automatically the resistivity will increase as they are the factors affecting the resistivity
Last Answer : A wire of resistance R has it length and cross-section both doubled. Its resistance will become R.
Description : If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes?
Last Answer : If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes 0.4 ohm.
Description : A metal rod of length l cuts across a uniform magnetic field B with a velocity v. If the resistance of the circuit of which the rod forms a part is r,
Last Answer : A metal rod of length l cuts across a uniform magnetic field B with a velocity v. If the resistance of the circuit of ... lv)/(r)` D. `(Blv^(2))/(r)`
Description : In the circuit diagram shown in figure, potential difference across `3Omega` resistance is 20 V. Then, match the following two columns.
Last Answer : In the circuit diagram shown in figure, potential difference across `3Omega` resistance is 20 V. Then, match the following two columns.
Description : According to Darcy's formula, the loss of head due to friction in the pipe is (where f = Darcy's coefficient, l = Length of pipe, v = Velocity of liquid in pipe, and d = Diameter of pipe) (A) flv²/2gd (B) flv²/gd (C) 3flv²/2gd (D) 4flv²/2gd
Last Answer : Answer: Option D
Description : The loss of head due to viscosity for laminar flow in pipes is (where d = Diameter of pipe, l = Length of pipe, v w = Specific weight of the flowing liquid) (A) 4 (B) 8 (C) 16 (D) 32
Description : A conducting wire of cross-sectional area `1 cm^(2)` has `3 xx 10^(23)` charge carriers per m3. If wire carries a current of `24 mA`, then drift veloc
Last Answer : A conducting wire of cross-sectional area `1 cm^(2)` has `3 xx 10^(23)` charge carriers per m3. If wire carries ... 3)ms^(-1)` D. `5xx10^(-6)ms^(-1)`
Description : A potentiometer wire is `100 cm` long hand a constant potential difference is maintained across it. Two cells are connected in series first to support
Last Answer : A potentiometer wire is `100 cm` long hand a constant potential difference is maintained across it. Two cells are connected ... C. `3 : 2` D. `5 : 1`
Description : Assertion : Inside a conductor, electrons have no motion in the absence of some potential difference across it. Reason : In the absence of potential d
Last Answer : Assertion : Inside a conductor, electrons have no motion in the absence of some potential difference ... D. If both Assertion and Reason are false.
Description : Pick out the wrong statement pertaining to the turbine agitator. (A) Recommended peripheral speed for the turbine agitator is 200-250 metres/minute (B) Pitched blade turbine agitator gives only radial flow with ... l/4th of agitator diameter (with central disc, it is l/8th of the agitator diameter)
Last Answer : (B) Pitched blade turbine agitator gives only radial flow with complete absence of the axial flow
Description : A circular flexible loop of wire of radius r carrying a current I is placed in a uniform magnetic field B . If B is doubled, then tension in the loop
Last Answer : A circular flexible loop of wire of radius r carrying a current I is placed in a uniform magnetic field ... is doubled C. is halved D. becomes 4 times
Description : When two concentric springs are made of same material, having same free length and compressed equally by axial load, then the load shared by each spring is proportional to (A) Spring index of each spring ... spring (C) Mean coil diameter of each spring (D) Square of wire diameter of each spring
Last Answer : (D) Square of wire diameter of each spring
Description : If number of coils are 8 and wire diameter of spring 3mm, then solid length is given by? a) None of the listed b) 27mm c) 24mm d) 21mm
Last Answer : c) 24mm
Description : Two copper wires A and B of equal masses are taken. The length of A is double the length of B. If the resistance of wire A is `160 Omega `, then calcu
Last Answer : Two copper wires A and B of equal masses are taken. The length of A is double the length of ... Omega `, then calculate the resistance of the wire B.
Description : In the circuit shown the voltage drop across the `15Omega` resistor is `30 V` having the polarity as indicated. The ratio of potential difference acro
Last Answer : In the circuit shown the voltage drop across the `15Omega` resistor is `30 V` having the ... difference across `5Omega` and resistance `R` is
Description : A potential difference of V = 100 ± 2 volt, when applied across a resistance R gives a current of 10 ± 0.5 ampere.
Last Answer : A potential difference of V = 100 2 volt, when applied across a resistance R gives a current of 10 ... percentage error in R given by R = V/I.
Description : The potential difference across a cell is 1.8 V when a current of 0.5 A is drawn from it. The p.d. falls to 1.6 V when a current of 1.0 A is drawn. Fi
Last Answer : The potential difference across a cell is 1.8 V when a current of 0.5 A is drawn from it. ... . Find the emf and the internal resistance of the cell.
Description : A cell which has an emf `1.5` V is connectedin series with an external resistance of `10Omega`. If the potential difference across the cell is `1.25`
Last Answer : A cell which has an emf `1.5` V is connectedin series with an external resistance of `10Omega`. If the potential ... `0.25` C. `1.5` D. `0.3`
Description : Current in a circuit if resistance of 15 Ω and potential difference of 3.0 V is applied across it's ends is A. 1 A B. 2 A C. 0.5 A D. 0.20 A
Last Answer : 0.20 A
Description : The potential difference across the gap of a spark plug ranges between a) 10-20 mV b) 10-20 V c) 10-20 kV d) 10-20 MV
Last Answer : ans a
Description : If the diameter of a capillary is doubled, then the rise of water in it will be – (1) two times (2) half (3) four times (4) no change
Last Answer : (2) half Explanation: Radius of a capillary tube is inversely proportional to the height of the liquid column. So, if radius of the tube is doubled, rise of level of water will becomes half ... to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity.
Description : For turbulent flow in a tube, the heat transfer co-efficient is obtained from the Dittus-Boelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of (A) 1 (B) 1.74 (C) 6.1 (D) 37
Last Answer : (C) 6.1
Description : A shaft of diameter d carries two discs at its two ends. The lowest torsional frequency is ω n . If the diameter is doubled, then the lowest torsional frequency becomes A 4ω n B ω n /2 C ω n /4 D 4ω n
Last Answer : D 4ω n
Description : If the diameter of a capillary is doubled, then the rise of water in it will be (1) two times (2) half (3) four times (4) no change
Last Answer : half
Description : A wire has resistance `12 Omega`. It is bent in the form of a circle. The effective resistance between two points across a diameter is.
Last Answer : A wire has resistance `12 Omega`. It is bent in the form of a circle. The effective resistance between two ... ` B. `6Omega` C. `3Omega` D. `24Omega`
Description : If L is the length of vehicles in metres, C is the clear distance between two consecutive vehicles (stopping sight distance), V is the speed of vehicles in km/hour, the maximum number N of vehicles/hour, is (A) N = 1000 V / (L + C ... ) / 1000 V (C) N = 1000 L / (C + V) (D) N = 1000 C / (L + V)
Last Answer : Answer: Option A
Description : A potentiometer circuit is setup as shown. The potential gradient across the potentiometer wire is `k "volt"//cm` and the ammeter present in the circu
Last Answer : A potentiometer circuit is setup as shown. The potential gradient across the potentiometer wire is `k "volt"//cm` and ... (2)` D. `kl_(1)"and"kl_(2)`
Description : A copper wire of diameter 0.16 cm is connected in series to an aluminium wire of diameter 0.25 cm. A current of 10 A is passed through them. Find (i)
Last Answer : A copper wire of diameter 0.16 cm is connected in series to an aluminium wire of diameter 0.25 cm. A ... of aluminium wire is `10^(29) m^(-3)`.
Description : The temperature coefficient of copper is `0.004^(@)C^(-1)`. Find the resistance of a 5 m long copper wire of diameter 0.2 mm at `100^(@)C`, if the res
Last Answer : The temperature coefficient of copper is `0.004^(@)C^(-1)`. Find the resistance of a 5 m long copper wire of ... `0^(@)C` is `1.7xx10^(-8) Omega` m.
Description : What is the diameter of a copper wire to be used in a 16 km loop with a dc loop resistance of 100 ohms/km? A. 0.108 cm B. 1.082 cm C. 0.017 cm D. 0.0465 cm
Last Answer : D. 0.0465 cm