2492 + Interview Questions in CURRENT-ELECTRICITY IN GENERAL AWARENESS Page 29 InterviewSolution

1401.	A student has two wires of iron and copper of equal length and diameter. He first joins two wires in series and passes an electric current through the combination which increases gradually. After that he joins two wires in parallel and repeats the process of passing current. Which wire will glow first in each case?
Answer» (1) In series combination, there will be same current through Iron and as well as copper wire. Since the rate of heat production, `P = I^(2) R` or `P prop R` (for the given value of 1). The resistance of iron wire is more than that of copper for the given length and diameter. Hence in iron wire, the rate of heat production increases gradually. In series combination Iron will glow first. (2) In parallel combination of Iron and copper wire, there will be same P.D (V) across them. Since the rate of heat production, `P = (V^(2))/(R ) "or" P prop (1)/(R )` (for the given value fo V). The resistance of Iron is more than that of copper for the given length and diameter. Hence in copper wire, the rate of heat production is more. In parallel combination copper will glow first.

Discussion

1402.	In the network shown in fig. , points A, B, and C are at potentials of 70 V, 0, and 10V, respectively. A. the point D will be at a potential of 60 VB. the point D will be at a potential of 20 VC. currents in the pathes AD, DB and DC are in the ratio of `1:2:3`D. current in the paths AB, DB and DC are in the ratio of `3:2:1`
Answer» Correct Answer - C

Discussion

1403.	There are two wires of copper and iron of the same length but difference radii .When equal potential difference between the ends of each wire, the same current flows in them. What the ratio of their radii .Specific resistance of copper and irons are `1.6 xx 10^(-8) Omega m and 1.0 xx 10^(-7) Omega m` respectively
Answer» Correct Answer - `(2)/(5)` As, under the the same potential difference across the two wires, the same current flow in them to the resistance of two wires must be same Now,`R = (rhol)/(pi r^(2))` , So `R_(Cu) = (rho_(Cu)l)/(pi r_(Cu)^(2)) and R_(I) = (rho_(I)l)/(pi r_(I)^(2))` As `R_(Cu) = R_(I)` so `(rho_(Cu)l)/(pi r_(Cu)^(2)) = (rho_(I)l)/(pi r_(I)^(2))` or `(rho_(Cu))/(rho_(I)) = (r_(Cu)^(2))/(r_(I)^(2))` or `(r_(Cu))/(r_(I)) = sqrt((rho_(Cu))/(rho_(I))) = sqrt((1.6 xx 10^(-8))/(1.0 xx 10^(-7))) = 0.4 = (2)/(5)`

Discussion

1404.	Mark out the correct options (i) An ammeter should have small resistance (ii) An ammeter should have large resistance (iii) A voltage should have small resistance (iv) A voltage should have large resistance.A. (i),(ii)B. (ii),(iii)C. (iii),(iv)D. (i),(iv)
Answer» Correct Answer - D

Discussion

1405.	The net resistance of a volmeter should be large to ensure thatA. It does not get overheatedB. it does not draw excessive currentC. it can measure large potential differencesD. it does not appreciably change the potential difference to be measured.
Answer» Correct Answer - D

Discussion

1406.	n identical cells, each of emf E and internal resistance r, are joined in series to form a closed circuit. Find the potential difference across any one cell.A. zeroB. `epsilon`C. `(epsilon)/(n)`D. `((n-1)/(n)) epsilon`
Answer» Correct Answer - A

Discussion

1407.	In the circuit shown below, each battery is 5V and has an internal resistance of 0.2 ohm. The reading in the ideal voltmeter V is .A. 5 VB. 10 VC. 15 VD. zero
Answer» Correct Answer - D

Discussion

1408.	In the circuit shown below, each battery is 5V and has an internal resistance of 0.2 ohm. The reading in the ideal voltmeter V is .
Answer» All the eight batteries are in series Total emf of eight betteries `= 6 xx 8 = 48V` Total initialresistance of eight batteries `= 8 xxx 0.2 = 1.4 Omega` current `t = (48)/(1.6) = 30A` Reading of veltmeter = terminal potential different across one cell = mgf - voltage across initial resistance of time of one cell `= 6 - 30 xx 0.2 = 0 V`

Discussion

1409.	In the circuit shown below, each battery is 5V and has an internal resistance of 0.2 ohm. The reading in the ideal voltmeter V is .
Answer» Let a current I flow through the circuit. Net emf of the circuit `= 8(5V) = 40V` Net resistance in the circuit `= 8(0.2 Omega) = 1.6Omega` Current flowing through the circuit, `I = (40 V)/(1.6Omega) = 25 A` The voltmeter reading would be `V = E-IR = (5V)-(25A)(0.2Omega)` `=5V-5V = 0`.

Discussion

1410.	Six resistance are connected as shown in figure. If total current flowing is `0.5A`, then the potrential difference `V_(A)-V_(B)` is A. 8 VB. 6 VC. 2 VD. 4 V
Answer» Correct Answer - D

Discussion

1411.	Some electric bulbs are connected in series across a 220 V supply in a room. If one bulb is fused then remaining bulbs are connected again in series across the same supply. The illumination in the room willA. increaseB. decreaseC. remain the sameD. not continuous
Answer» Correct Answer - A

Discussion

1412.	A uniform wire when connected directly across a 220 V line produces heat H per second. If wire is divided into n parts and all parts are connected in parallel across a 200 V line, then the heat produced per second will beA. `H_(s)`B. `nH_(s)`C. `n^(2)H_(s)`D. `H_(s)//n^(2)`
Answer» Correct Answer - C V=200 V ` H=i^(2)Rt " " (because i=V//r)` `H_(s)=(V^(2))/(nR_(eq))t` In parallel, equivalent resistance of n parts is ` R_(eq)=(r )/(n)` where, r is the resistance of each part. `H=(V^(2))/((r//n))t=(nV^(2))/(t)t` `therefore " " H=n^(2)H_(s)`

Discussion

1413.	If a wire is stretched to four times its length, then the specific resistance of the wire willA. become 4 timesB. become 1/4 timesC. become 16 timesD. remain the same
Answer» Correct Answer - D

Discussion

1414.	For the circuit shown in figure given below, the equivalent resistance points A and B is A. `10Omega`B. `5 Omega`C. `(10)/(3)Omega`D. `2Omega`
Answer» Correct Answer - C

Discussion

1415.	Two resistors of `6 Omega " and " 9 Omega` are connected in series to a 120 V source. The power consumed by the `6 Omega` resistor isA. 384 WB. 616 WC. 1500 WD. 1800 W
Answer» Correct Answer - A

Discussion

1416.	Two resistors of `6 Omega " and " 9 Omega` are connected in series to a 120 V source. The power consumed by the `6 Omega` resistor isA. 384 WB. 576 WC. 1500 WD. 1800 W
Answer» Correct Answer - A V=120 V `V=V_(1)+V_(2)` `V_(1)=iR_(1)` `V_(2)=iR_(2) implies (V_(1))/(R_(1)) =(V_(2))/(R_(2))` From Eq. (i), `V=V_(1)+V_(2)=V_(1)+(R_(2))/(R_(1))V_(1)` `V=V_(1)[(R_(1)+R_(2))/(R_(1))] implies V_(1)=(120xx6)/(15)=48 V` Power in ` 6 Omega, P_(1)=(V_(1)^(2))/(R_(1))=(48xx48)/(6)implies P_(1)=384 W`

Discussion

1417.	A 100 W, 200 V bulb is connected to a 160 V supply. The power consumption would beA. 64 WB. 80 WC. 100 WD. 150 W
Answer» Correct Answer - A `P=V^(2)//R=160xx(160)/(400)=64 W`

Discussion

1418.	Assertion: Current is a scalar quantity. Reason: Electric current arises due to continuous flow of charged particles or ions.A. If both Assertion `&` Reason are True `&` the Reason is a correct explanantion of the AssertionB. If both Assertion `&` Reason True but Reason is not a correct explanation of the AssertionC. If Assertion is True but the Reason is FalseD. If both Assertion `&` Reason are False.
Answer» Correct Answer - 2

Discussion

1419.	The dimensions of a block are `1cmxx1cmxx100cm.` If the specific resistance of its material is `2xx10^(-7) ohmxxmetre`, then the resistance between the opposite rectangular faces isA. `2xx10^(-9) Omega`B. `2xx10^(-7) Omega`C. `2xx10^(-5) Omega`D. `2xx10^(-3) Omega`
Answer» Correct Answer - B `R=(rhol)/A=(2xx10^(-7)xx1xx10^(-2))/(1xx100xx10^(-4))=2xx10^(-7) Omega`

Discussion

1420.	In the same figure, equivalent resistance between points A and D isA. `(R)/(4)`B. `2R`C. `R`D. `(R)/(2)`
Answer» Correct Answer - D

Discussion

1421.	One mole of an ideal gas undergoes a process `p=(p_(0))/(1+((V_(0))/(V))^(2))`. Here, `p_(0)` and `V_(0)` are constants. Change in temperature of the gas when volume is changed from `V=V_(0)` to `V=2V_(0)` isA. `-(2p_(0)V_(0))/(5R)`B. `(11p_(0)V_(0))/(10R)`C. `-(5p_(0)V_(0))/(4R)`D. `p_(0)V_(0)`
Answer» Correct Answer - B

Discussion

1422.	Three wires of same material are connected in parallel to a source of emf. The length ratio of the wires is `1:2:3` and the ratio of their area of cross section is `2:4:1` then match the following
Answer» Correct Answer - `(A)R, (B)P,(C)P`

Discussion

1423.	A solid body X of very large heat capacity is kept in an atmosphere whose temperature is 300 K. The body X is connected to a rod of length 1 m and cross sectional area S, as shown in the figure. Thermal conductivity of rod AB is `0.0567W//mK`. Assuming that there is no heat exchange with the surrounding except fom the end B of the rod i.e., neither by any surface of X nor by the curved surface of rod. The end B has emissivity `e=0.8`. If the steady state temperature of the end B is 400 K then find the temperature of X in steady state. (Stefan constant `sigma-5.67xx10^(-8)W//m^(2)K^(4)`) A. 14400 KB. 12600 KC. 13000 KD. 12000 K
Answer» Correct Answer - A

Discussion

1424.	There are two types of rods : Rod 1 : Length L, Thermal conductivity D, Area of cross section A Rod 2 : Length 2L, Thermal conductivity K, Area of cross section A Four possible arrangements of these rods in steady state are shown in Table-1 and Table-2 gives the temperature of the junction. Match Table-1 with Table-2
Answer» Correct Answer - (A) S, (B) R, (C) Q, (D) P

Discussion

1425.	Two wires A and B of same material end mass have their length is the ratio `1: 3`. On connecting them, one at a time in the same source of emf, the rate of heat dissipated in `B` is `10 W`. What is the rate of heat dissipated in A ?
Answer» Correct Answer - `90 W` Let `a_(1) ,l_(1)` be the area of cross - section and length of wire A and `a_(2),l_(2)` be the area of cross - section and length of wire B .As the two wire are of same meterial and mass , so their volume is same .Hence `a_(1) l_(1) = a_(2),l_(2) or (a_(1))/(a_(2)) = (i_(1))/(l_(2)) = (3l)/(I) = 3 or a_(1) = 3a_(2)` If `epsilon` is the emf of the source , then the rate of dissipation of heat in wire B is `H_(B) = (epsilon^(2))/(R_(2)) = 10 or (epsilon^(2))/(rho l_(2)//a_(2)) = 10 ` or `(epsilon^(2))/(rho 3//l a_(2)) = 10 or (epsilon^(2)a_(2))/(rho l) = 30 [," l_(2) = 3 l]` Rate of head dissipation in wire A is `H_(A) = (epsilon^(2))/(R_(1)) = (epsilon^(2))/(rho lla_(1)) = (epsilon^(2))/(rho l) (3a_(2))` `= 3 xx 30= 90 W`

Discussion

1426.	The shunt required for 10% of main current to be sent through the moving coil galvanometer of resistance `99 Omega` will be-A. `9.9Omega`B. `10Omega`C. `11Omega`D. `9Omega`
Answer» Correct Answer - C

Discussion

1427.	A resistor of resistance R is connected to an ideal battery. If the value of R is decreased,the power dissipated in the resistor willA. increaseB. decreaseC. remain unchangedD. None of these
Answer» Correct Answer - B

Discussion

1428.	A platinum resistance thermometer makes use of the variation of a conductor with temperature. If the resistance of this thermometer is `5 Omega " at " 20^(@)C " and " 16 Omega` when inserted in a furnace, find the temperature of the furnace. Given `alpha` for the platinum `=0.0036^(@)C`.
Answer» Correct Answer - `631^(@)C`

Discussion

1429.	An electric toaster uses nichrome for its heating element. When a negligibly small current passes through it. It resistance at room temperature `(27.0^@C)` is found to be `75.3Omega`. When the toaster is connected to a `230 V` supply, the current settles, after a few seconds, to a steady value of `2.68 A`. What is steady temperature of the nichrome element? The temperature coefficient of resistance of nichrome averaged over the temperature range involved , `1.70xx10^-4C^-1`
Answer» Correct Answer - `847^(@)C`

Discussion

1430.	Compute total circuit resistance and battery current as shown in figure.
Answer» Correct Answer - A::C All these resistors are in parallel.

Discussion

1431.	Calculate the potentials of points `A, B,C` and `D` as shown in Fig. a. What would be the new potential values if connections of `6 V` battery are reversed as shown in fig b. All resistance are on ohm.
Answer» Correct Answer - A::B::C::D First case `i=(12+6)/(1+2+3)=3A` (clock wise) `Now, V_A-V_G=12V` `:. V_A=12V,as V+G=0` `V_A-V_B=1xx3=3V` `:. V_B=V_A-3=9V` `V_B-V_C=2xx3=6V` `:. V_C=V_B-6=3V` `V_G-V_D=6V` `V_D=-6V, as V_G=0` in the second case `i=(12-6)/(1+2+3)=1A` Rest procedure is same

Discussion

1432.	Assertion : In our houses when we start switching on different light buttons, main current goes on increasing. Reason : Different connections in houses are in parallel. When we start switching on different light buttons, then net resistance of the circuit decreases. Therefore, main current increases.A. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.B. If both Assertion and Reason are true and Reason is not correct explanation of Assertion.C. If Assertion is true but Reason is false.D. If Assertion is false but Reason is true.
Answer» Correct Answer - A

Discussion

1433.	In a conductor 4 coulombs of charge flows for 2 seconds . The value of electric current will beA. 4 voltsB. 4 amperesC. 2 amperesD. 2 volts
Answer» Correct Answer - C

Discussion

1434.	A wire is stretched as to change its diameter by 0.25%. The percentage change in resistance isA. `4.0%`B. `2.0%`C. `1.0%`D. `0.5%`
Answer» Correct Answer - C

Discussion

1435.	A Leclanche cell of emf 1.46 V balances against 292 cm of a potentio meter wire. If the current through the wire is 400 mA, the resistance per unit length of the potentiometer wire is
Answer» \(\frac{E_1}{l_1}=I\lambda\) \(\therefore \lambda=\frac{E_1}{Il_1}\) \(=\frac{1.46}{(0.4)(2.92)}\) \(\lambda=\frac{1.46}{1.168}\) \(\lambda=1.25\Omega/m\)

1435.

A Leclanche cell of emf 1.46 V balances against 292 cm of a potentio meter wire. If the current through the wire is 400 mA, the resistance per unit length of the potentiometer wire is

Answer»

\(\frac{E_1}{l_1}=I\lambda\)

\(\therefore \lambda=\frac{E_1}{Il_1}\)

\(=\frac{1.46}{(0.4)(2.92)}\)

\(\lambda=\frac{1.46}{1.168}\)

\(\lambda=1.25\Omega/m\)

Discussion

1436.	The emf `varepsilon` of a Cu-Fe thermocouple varies with the temperature `theta` of the hot junction (cold junction at `0^(@)C` ), as `varepsilon(mu V)=14 theta-0.02 theta^(2)` Determine the neutral temperature.
Answer» At neutral temperature `(dE)/(dtheta)=0 therefore 14-2(0.02theta_(n))=0rArr theta_(n)=(14)/(0.04)=350^(@)C`

Discussion

1437.	A steady current of `10.0` A is maintained in a copper voltameter . Calculate the time required to deposit `2.5` g of copper . Relative atomic mass of copper = `63.5` g .
Answer» `because m`=Zit and `Z=(E)/(F)=(M)/(pF) therefore m=(Mit)/(pF)` where m=2.5g. `F=96500C//"mol",M=63.5,i=10A` and p=2 `therefore t=(mpF)/(Mi)=(2.5xx2xx96500)/( 63.5xx10)= 760s`

Discussion

1438.	A copper voltameter is connected in series with a coil of resistance `100Omega`. A steady current flowing in the circuit for 10 minutes, gives a deposit of 0.1 g of copper in the voltameter. Calculate the heat generated in the resistance coil. (ECE of Cu`3.3xx10^(-7)kg//C`)
Answer» From first law of electrolysis, m=Zit `rArr I=(m)/(Zt)=(0.1xx10^(-3))/(3.3xx10^(-7)xx600)=0.505A` Heat generated in the resistance coil `=I^(2)Rt=(0.505)^(2)(100) 600=15301 J`

Discussion

1439.	A current of `2 A` flows through a `2 Omega` resistor when connected across a battery. The same battery supplies a current of `0.5 A` when connected across a `9 Omega` resistor. The internal resistance of the battery isA. `1//3Omega`B. `1//4Omega`C. `1Omega`D. `0.5Omega`
Answer» Correct Answer - A

Discussion

1440.	In the figure given the value of X resistance will be, when the p.d. between `B` and `D` is zero A. 4 ohmB. 6 ohmC. 8 ohmD. 9 ohm
Answer» Correct Answer - C Balanced Wheatstone bridge `((6 + 15))/((15 +(6)/(2))) = (((8 X)/(8 + X)+3))/((4 + (4)/(2)))` `(21)/(18) = (((8X)/(8 + X)+3))/(6)` `(8X)/(8 +X) = 4 rArr X = 8 Omega`.

Discussion

1441.	A current `I` is passing through a wire having two sections `P` and `O` of uniform diameters `d` and `d//2` respectively. If the mean drift velocity of electrons in section `P` and `Q` is denoted by `v_(P)` and `v_(Q)` respectively, thenA. `v_(P) = v_(Q)`B. `v_(P) = (1)/(2) v_(Q)`C. `v_(P) = (1)/(4) v_(Q)`D. `v_(P) = 2v_(Q)`
Answer» Correct Answer - C (c ) Drift velocity `v_(d) = (i)/(n e A) implies v_(d) prop (1)/(A)` or `v_(d) prop (1)/(d^(2))` `implies (v_(P))/(v_(Q)) = ((d_(Q))/(d_(P)))^(2) = ((d // 2)/(d))^(2) = (1)/(4) implies v_(P) = (1)/(4) v_(Q)`

Discussion

1442.	It is desired to make a long cylindrical conductor whose temperature coefficient of resistivity at `20^(@)C` will be close to zero. If such a conductor is made by assembling alternate disks of iron and carbon, find the ratio of the thickness of a carbon disk to that an iron disk. `("For carbon", p = 3500 xx 10^(-8)Omega m and alpha= -0.50 xx 10^(-3) .^(@)C^(-1) "for iron, p"=9.68 xx 10^(-8)Omega m and alpha=6.5 xx 10^(-3).^(@)C^(-1))`A. 0.36B. 0.036C. 1D. 2
Answer» Correct Answer - B The direction of currently density is the direction of flow of positive charge in the circuit which is possible due to electric field produced by charges accumulated on the surface of wire.

Discussion

1443.	`E` denotes electric field in a uniform conductor, `I` corresponding current through it, `v_(d)` velocity of electrons and `P` denotes thermal power produced in the conductor, then which of the following graph is correct?A. B. C. D.
Answer» Correct Answer - C (c ) `E = (iR)/(L) = (i. rho)/(A) = (n e Av d rho)/(A) implies v_(d) prop E` (Straight line) `P = i^(2) R = ((EA)/(rho))^(2) R implies P prop E^(2)` (Symmetric parabola) Also `P prop i^(2)` (parabola) Hence, all graphs `a, b, c, d` are correct and `c` is incorrect.

Discussion

1444.	The V - I graph for a conductor makes angle `theta` with V-axis. Here V denotes voltage and I denotes current. What is the resistance of this conductor?A. `sin theta`B. `cos theta`C. `tan theta`D. `cot theta`
Answer» Correct Answer - D Slope of graph ` = tan ( 90-theta)=(V)/(I)=R` `:.cot theta=R`

Discussion

1445.	`E` denotes electric field in a uniform conductor, `I` corresponding current through it, `v_(d)` velocity of electrons and `P` denotes thermal power produced in the conductor, then which of the following graph is correct?A. B. C. D.
Answer» Correct Answer - a,b,d `upsilon_(d) = (eE)/(m) tau` i.e. `upsilon_(d)prop E` `P = (V^(2))/(R ) = ((E//d)^(2))/(R ) = (E^(2))/(d^(2)R)`, i.e. `P prop b E^(2)` But `E prop upsilon_(d)` so `P prop upsilon_(d)^(2)` `P = VI = I^(2) R`, i.e. `P prop I^(2)`

Discussion

1446.	Three resistors `1 Omega, 2 Omega` and `3 Omega` are combined in series. What is the total resistance of the comination?
Answer» Here `R_(1) = 1 Omega, R = 2 Omega, R_(3) = 3 Omega, V = 12 V` In series total resistance `R__(s) = R_(1) + R_(2) + R_(3) = 1+ 2 + 3 = 6 Omega`

Discussion

1447.	As the temperature of a metal conductors increase the frequency of collision of electrons …….. and time of relation of the electrons……
Answer» Correct Answer - increase : decrease

Discussion

1448.	The mean time internal of two consecutive collisiion of the electron with positive ion in a conductor is called …….
Answer» Correct Answer - Time of relacation

Discussion

1449.	Consider positive and negative charge (all of equal magnitude) moving horizontally through two conductor A and B The magnitude of current is ……..in A and ……. In B
Answer» Correct Answer - more : less

Discussion

1450.	Current is a…….quantity and in `SI` unit is……..
Answer» Correct Answer - scaller, ampare

Discussion

Explore topic-wise InterviewSolutions in .

Mark out the correct options (i) An ammeter should have small resistance (ii) An ammeter should have large resistance (iii) A voltage should have small resistance (iv) A voltage should have large resistance.A. (i),(ii)B. (ii),(iii)C. (iii),(iv)D. (i),(iv)

The net resistance of a volmeter should be large to ensure thatA. It does not get overheatedB. it does not draw excessive currentC. it can measure large potential differencesD. it does not appreciably change the potential difference to be measured.

n identical cells, each of emf E and internal resistance r, are joined in series to form a closed circuit. Find the potential difference across any one cell.A. zeroB. `epsilon`C. `(epsilon)/(n)`D. `((n-1)/(n)) epsilon`

In the circuit shown below, each battery is 5V and has an internal resistance of 0.2 ohm. The reading in the ideal voltmeter V is .A. 5 VB. 10 VC. 15 VD. zero

In the circuit shown below, each battery is 5V and has an internal resistance of 0.2 ohm. The reading in the ideal voltmeter V is .

In the circuit shown below, each battery is 5V and has an internal resistance of 0.2 ohm. The reading in the ideal voltmeter V is .

Six resistance are connected as shown in figure. If total current flowing is `0.5A`, then the potrential difference `V_(A)-V_(B)` is A. 8 VB. 6 VC. 2 VD. 4 V

Some electric bulbs are connected in series across a 220 V supply in a room. If one bulb is fused then remaining bulbs are connected again in series across the same supply. The illumination in the room willA. increaseB. decreaseC. remain the sameD. not continuous

A uniform wire when connected directly across a 220 V line produces heat H per second. If wire is divided into n parts and all parts are connected in parallel across a 200 V line, then the heat produced per second will beA. `H_(s)`B. `nH_(s)`C. `n^(2)H_(s)`D. `H_(s)//n^(2)`

If a wire is stretched to four times its length, then the specific resistance of the wire willA. become 4 timesB. become 1/4 timesC. become 16 timesD. remain the same

For the circuit shown in figure given below, the equivalent resistance points A and B is A. `10Omega`B. `5 Omega`C. `(10)/(3)Omega`D. `2Omega`

Two resistors of `6 Omega " and " 9 Omega` are connected in series to a 120 V source. The power consumed by the `6 Omega` resistor isA. 384 WB. 616 WC. 1500 WD. 1800 W

Two resistors of `6 Omega " and " 9 Omega` are connected in series to a 120 V source. The power consumed by the `6 Omega` resistor isA. 384 WB. 576 WC. 1500 WD. 1800 W

A 100 W, 200 V bulb is connected to a 160 V supply. The power consumption would beA. 64 WB. 80 WC. 100 WD. 150 W

The dimensions of a block are `1cmxx1cmxx100cm.` If the specific resistance of its material is `2xx10^(-7) ohmxxmetre`, then the resistance between the opposite rectangular faces isA. `2xx10^(-9) Omega`B. `2xx10^(-7) Omega`C. `2xx10^(-5) Omega`D. `2xx10^(-3) Omega`

In the same figure, equivalent resistance between points A and D isA. `(R)/(4)`B. `2R`C. `R`D. `(R)/(2)`

One mole of an ideal gas undergoes a process `p=(p_(0))/(1+((V_(0))/(V))^(2))`. Here, `p_(0)` and `V_(0)` are constants. Change in temperature of the gas when volume is changed from `V=V_(0)` to `V=2V_(0)` isA. `-(2p_(0)V_(0))/(5R)`B. `(11p_(0)V_(0))/(10R)`C. `-(5p_(0)V_(0))/(4R)`D. `p_(0)V_(0)`

Three wires of same material are connected in parallel to a source of emf. The length ratio of the wires is `1:2:3` and the ratio of their area of cross section is `2:4:1` then match the following

Two wires A and B of same material end mass have their length is the ratio `1: 3`. On connecting them, one at a time in the same source of emf, the rate of heat dissipated in `B` is `10 W`. What is the rate of heat dissipated in A ?

The shunt required for 10% of main current to be sent through the moving coil galvanometer of resistance `99 Omega` will be-A. `9.9Omega`B. `10Omega`C. `11Omega`D. `9Omega`

A resistor of resistance R is connected to an ideal battery. If the value of R is decreased,the power dissipated in the resistor willA. increaseB. decreaseC. remain unchangedD. None of these

A platinum resistance thermometer makes use of the variation of a conductor with temperature. If the resistance of this thermometer is `5 Omega " at " 20^(@)C " and " 16 Omega` when inserted in a furnace, find the temperature of the furnace. Given `alpha` for the platinum `=0.0036^(@)C`.

Compute total circuit resistance and battery current as shown in figure.

Calculate the potentials of points `A, B,C` and `D` as shown in Fig. a. What would be the new potential values if connections of `6 V` battery are reversed as shown in fig b. All resistance are on ohm.

In a conductor 4 coulombs of charge flows for 2 seconds . The value of electric current will beA. 4 voltsB. 4 amperesC. 2 amperesD. 2 volts

A wire is stretched as to change its diameter by 0.25%. The percentage change in resistance isA. `4.0%`B. `2.0%`C. `1.0%`D. `0.5%`

A Leclanche cell of emf 1.46 V balances against 292 cm of a potentio meter wire. If the current through the wire is 400 mA, the resistance per unit length of the potentiometer wire is

The emf `varepsilon` of a Cu-Fe thermocouple varies with the temperature `theta` of the hot junction (cold junction at `0^(@)C` ), as `varepsilon(mu V)=14 theta-0.02 theta^(2)` Determine the neutral temperature.

A steady current of `10.0` A is maintained in a copper voltameter . Calculate the time required to deposit `2.5` g of copper . Relative atomic mass of copper = `63.5` g .

A copper voltameter is connected in series with a coil of resistance `100Omega`. A steady current flowing in the circuit for 10 minutes, gives a deposit of 0.1 g of copper in the voltameter. Calculate the heat generated in the resistance coil. (ECE of Cu`3.3xx10^(-7)kg//C`)

A current of `2 A` flows through a `2 Omega` resistor when connected across a battery. The same battery supplies a current of `0.5 A` when connected across a `9 Omega` resistor. The internal resistance of the battery isA. `1//3Omega`B. `1//4Omega`C. `1Omega`D. `0.5Omega`

In the figure given the value of X resistance will be, when the p.d. between `B` and `D` is zero A. 4 ohmB. 6 ohmC. 8 ohmD. 9 ohm

`E` denotes electric field in a uniform conductor, `I` corresponding current through it, `v_(d)` velocity of electrons and `P` denotes thermal power produced in the conductor, then which of the following graph is correct?A. B. C. D.

The V - I graph for a conductor makes angle `theta` with V-axis. Here V denotes voltage and I denotes current. What is the resistance of this conductor?A. `sin theta`B. `cos theta`C. `tan theta`D. `cot theta`

`E` denotes electric field in a uniform conductor, `I` corresponding current through it, `v_(d)` velocity of electrons and `P` denotes thermal power produced in the conductor, then which of the following graph is correct?A. B. C. D.

Three resistors `1 Omega, 2 Omega` and `3 Omega` are combined in series. What is the total resistance of the comination?

As the temperature of a metal conductors increase the frequency of collision of electrons …….. and time of relation of the electrons……

The mean time internal of two consecutive collisiion of the electron with positive ion in a conductor is called …….

Consider positive and negative charge (all of equal magnitude) moving horizontally through two conductor A and B The magnitude of current is ……..in A and ……. In B

Current is a…….quantity and in `SI` unit is……..