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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
Match the following two tables. |
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Answer» Correct Answer - (A) R, (B) Q, (C) P,(D) S |
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| 252. |
The figures given below show different processes (relating pressure P and volume V) for a given amount of an ideal gas. W is work done by the gas and `DeltaQ` is heat absorbed by the gas. |
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Answer» Correct Answer - (A) PS, (B) Q, (C) PS, (D) QR |
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| 253. |
One mole of an ideal monotomic gas undergoes a linear process from A to B in which its pressure p and its volume V change as shown in figure. The absolute temperature T versus volume V for the given process isA. B. C. D. |
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Answer» Correct Answer - C |
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| 254. |
A composite rod made of three rods of equal length and cross-section as shown in fig. The thermal conductivites of the materials of the rods are `K//2`, `5K` and `K` respectively. The end `A` and end `B` are at constant tempertures. All heat entering the face `A` goes out of the end `B` there being no loss of heat from the sides of the bar. The effective thermal conductivity of the bar is A. `15K//16`B. `6K//13`C. `5K//16`D. `2K//13` |
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Answer» Correct Answer - A |
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| 255. |
One mole of an ideal monoatomaic gas is taken from `A` to `C` along the path `ABC` . The temperature of the gas at `A` is `T_(0)` . For the process `ABC` : A. work done by the gas is `R T_(0)`B. change in internal energy of the gas is `(11)/(2)R T_(0)`C. heal absorbed by the gas is `(11)/(2)R T_(0)`D. heat absorbed by the gas is `(13)/(2)R T_(0)` |
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Answer» Correct Answer - A::C |
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| 256. |
A meter bridge is balanced by putting `20pi` resistance in the left gap and `40pi` in the right, gap, if `40pi` resistance is now shunted with `40pi` resistance the shift in the null point towards right is nearlyA. 16.67 cmB. 50 cmC. 25 cmD. 70.67 cm |
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Answer» Correct Answer - A For balanced bridge, `(X)/(R)=(l_(x))/(l_(r)) rArr (20)/(40)=(l_(x))/(l_(r))` `:.2l_(x)=l_(r)=(100-l_(x)) " " :.l_(x)=33.33 cm` Now, `40 Omega` . Thus, `R=(40xx40)/(40+40)=20Omega` Thus, to balanced bridge again, `(20)/(20)=(l_(x))/(l_(r))` `:.l_(x)=l_(r)=50cm` Thus, shift in null point is, `50-33.33=16.67cm` |
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| 257. |
A metre bridge is balanced with known resistance in the right gap and a metal wire in the left gap. If the metal wire is heated the balance point.A. shifts towards leftB. shifts towards rightC. does not changeD. may shift towards left or right depending on the nature of the metal. |
| Answer» Correct Answer - B | |
| 258. |
The quantity `PV//kT` representsA. number of moles of the gasB. total mass of the gasC. number of molecules in the gasD. density of the gas |
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Answer» Correct Answer - C |
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| 259. |
A wire of length L and 3 identical cells of negligible internal resistance are connected in series. Due to the current, the temperature of the wire is raised by `DeltaT` in a time t. A number N of similar cells is now connected in series with a wire of the same material and cross-section but of length 2L. The temperature of the wire is raised by the same amount `DeltaT` in the same time t. the value of N isA. 4B. 6C. 8D. 9 |
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Answer» Correct Answer - B (b) Let `R` and `m` the resistance and mass of the first wire, then the second wire has resistance `2R` and mass `2 m`. Let `E =` emf of each cell, `S =` specific heat capacity of the material of the wire. For the first wire, current `i_(1) = (3 E)/(R )` and `i_(2) = (NE)/(2R) = mS Delta T` For the second wire, `i_(2) = (NE)/(2R)` and `i_(2)^(2) (2 R) t = 2 m S Delta T`. Thus, `i_(1) = i_(2)` or `N = 6`. |
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| 260. |
A wire of length L and 3 identical cells of negligible internal resistance are connected in series. Due to the current, the temperature of the wire is raised by `DeltaT` in a time t. A number N of similar cells is now connected in series with a wire of the same material and cross-section but of length 2L. The temperature of the wire is raised by the same amount `DeltaT` in the same time t. the value of N isA. `4`B. `6`C. `8`D. `9` |
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Answer» Correct Answer - B `H=(V^(2))/Rt=mCDeltaTimplies((3E)^(2))/R t=RmCDeltaT` `(3E)^(2)t=rhoL/A(dAL)CDeltaT` `(3E)^(2)t=rhodL^(2)CDeltaT....(1)` `(nE)^(2)t=rhodL(2L)^(2)CDeltaL...(2)` From `(1)` and `(2), n=6` |
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| 261. |
A wire of length L and 3 identical cells of negligible internal resistance are connected in series. Due to the current, the temperature of the wire is raised by `DeltaT` in a time t. A number N of similar cells is now connected in series with a wire of the same material and cross-section but of length 2L. The temperature of the wire is raised by the same amount `DeltaT` in the same time t. the value of N isA. 3B. 2C. 6D. 4 |
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Answer» Correct Answer - C In the first case, three identical cells are connected in series with a wire of length L. let the terminal potential difference of each cell is V and resistance of the wire is R. Then heat developed in the wire in time t is `H=((3V)^(2))/(R)t=msDeltaT` where m is the mass of the wire, s-the specific heat of its material and `DeltaT` is the rise in its temperature. When N such identical cells are connected in series, the effective terminal otential is NV volt ad if the length of the wire is doubled, its resistance and mass also doubled. Then heat develope in the wire is `H=((NV)^(2))/(2R)t=(2m)s.DeltaT` DIviding both the equations, we get `(N^(2))/(2xx9)=2impliesN=6` |
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| 262. |
Electric bulb `50 W - 100 V` glowing at full power are to be used in parallel with battery `120 V`, `10 Omega`. Maximum number of bulbs that can be connected so that they glow in full power isA. 2B. 8C. 4D. 6 |
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Answer» Correct Answer - C |
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| 263. |
Three bulbs with their power and working voltage are connected as shown in the circuit diagram to a 12 V battery. The total power consumed by the bulbs is (ignore the internal resistance of the battery shown)A. 24 WB. 12 WC. 6 WD. 15 W |
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Answer» Correct Answer - C `P=(V^(2))/(R)` |
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| 264. |
A battery of emf V and internal resistance `r` is connected to N identical bulbs, all in parallel. Resistance of each bulb is R. It is observed that maximum cumulative power is dissipated in the bulbs if `N = 10`. Can we say that `r=(R)/(10)` |
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Answer» Correct Answer - No |
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| 265. |
The tungsten filaments of two electric bulbs are of the same length. If one of them gives 25 W power and the other 60 W power, thenA. Both the filaments are of same thicknessB. 25 W bulb has thicker filamentC. 60 W bulb has thicker filamentD. Both the filaments have same cross-sectional area |
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Answer» Correct Answer - C |
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| 266. |
The storage battery of a car has an emf of 12 V. If the inernal resistance of the battery of `0.4 Omega`, What is the maximum current that can be drawn from the battery ? |
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Answer» Here, `epsilon = 12 V, r = 0.4 Omega` Maximum current `I_(max) = epsilon/r = 12/0.4 = 30A` |
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| 267. |
One end of a Nichrome wire of length `2L` and cross-sectional area `A` is attached to an end of another Nichrome wire of length `L` and cross-sectional area `2A`. If the free end of the longer wire is at an electric potential of `8.0` volts, and the free end of the shorter wire is at an electric potential `1.0` volts, the potential at the junction of the two wires is equal toA. 2.4 VB. 3.2 VC. 4.5 VD. 5.6 V |
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Answer» Correct Answer - A |
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| 268. |
A series parallel combination battery consisting of a large number `N = 300` of identical cells, each will an inernal resistance `r = 0.3 Omega`, is loaded with an external resistances `R = 10 Omega`. Find the number `n` of parallel groups consisting of an equal number of cells connected in series, at which the external resistance generates the highest thermal power.A. 2B. 3C. 4D. 6 |
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Answer» Correct Answer - B |
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| 269. |
2 moles of an ideal monoatomic gas undergoes a cyclic process ABCA as shown in the figure. R is the univers l gas constant. `("given ln 2"=0.693)` Answer the following questions Percentage efficiency of the cycle is (approximately)A. `10.38%`B. `13.2%`C. `40.38%`D. `25.2%` |
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Answer» Correct Answer - B |
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| 270. |
2 moles of an ideal monoatomic gas undergoes a cyclic process ABCA as shown in the figure. R is the univers l gas constant. `("given ln 2"=0.693)` Answer the following questions Graph of pressure versus volume of the cyclic process ABCA isA. B. C. D. None of these |
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Answer» Correct Answer - C |
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| 271. |
2 moles of an ideal monoatomic gas undergoes a cyclic process ABCA as shown in the figure. R is the univers l gas constant. `("given ln 2"=0.693)` Answer the following questions Graph of pressure versus volume of the cyclic process ABCA isA. B. C. D. None of these |
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Answer» Correct Answer - B |
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| 272. |
Pressure versus density graph of an ideal gas is shown in figure A. during the process AB work done by the gas is positiveB. during the process AB work done by the gas is negativeC. during the process BC internal energy of the gas is increasingD. None of the above |
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Answer» Correct Answer - D |
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| 273. |
Themperature of a body `theta` is slightly more than the temperature of the surrounding `theta_(0)` its rate of cooling `(R )` versus temperature of body `(theta)` is plotted its shape would be .A. B. C. D. |
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Answer» Correct Answer - B |
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| 274. |
The reading of the ammeter as per figure shown is A. `(1)/(8)A`B. `(3)/(4)A`C. `(1)/(2)A`D. `2A` |
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Answer» Correct Answer - B |
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| 275. |
Why are the connecting resistors in a meter bridge made of thick copper strips ? |
| Answer» The thick copper strips are used for connecting resistors as they offer minimum resistance and hence avoid error due to end resistance. The same (i.e., error due to end resistance) has not been taken into account in the bridge formula | |
| 276. |
A wire of resistance `R` is divided in 10 equal parts. These parts are connected in parallel, the equivalent resistance of such connection will beA. `0.01 R`B. `0.1 R`C. `10 R`D. `100 R` |
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Answer» Correct Answer - A (a) Each part will have a resistance `r = R//10` Let equivalent resistance be `r_(R)` then `(1)/(r_(R)) = (1)/(r ) + (1)/(r ) + (1)/(r )`……………….. 10 times `:. (r_(R)) = (10)/(r ) = (10)/(R//10) = (100)/(R ) implies r_(R) = (R )/(100) = 0.01 R` |
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| 277. |
The lowest resistance which can be obtained by connecting 10 resistors each of `1//10 ohm` isA. `1//250 Omega`B. `1//200 Omega`C. `1//100 Omega`D. `1//10 Omega` |
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Answer» Correct Answer - C |
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| 278. |
There are 8 equal resistances R . Two are connected in parallel, such four groups are connected in series, the total resistance of the system will beA. `R//2`B. `2R`C. `4R`D. `8R` |
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Answer» Correct Answer - B |
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| 279. |
Three resistance of one ohm each are connected in parallel. Such connection is again connected with `2//3 Omega` resistor in series. The resultant resistance will beA. `(5)/(3) Omega`B. `(3)/(2)Omega`C. `1 Omega`D. `(2)/(3) Omega` |
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Answer» Correct Answer - C |
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| 280. |
A wire of resistance `R` is divided in 10 equal parts. These parts are connected in parallel, the equivalent resistance of such connection will beA. `0.01R`B. `0.1R`C. `10R`D. `100R` |
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Answer» Correct Answer - A |
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| 281. |
Assertion: To draw more current at low P.d, parallel connection of cells is preferred. Reason: In parallel connection, current `i=(nE)/(r)` if `rgtgtR`A. Both (A) and (R) are true and (R) is the correct explanantion of A.B. Both (A) and (R) are true but (R) is not the correct explanation of A.C. (A) is true but (R) is falseD. (A) is false but (R) is true. |
| Answer» Correct Answer - A | |
| 282. |
Resistivity depen does resistivity depend on numberds uponA. cross section of conductorB. length of conductorC. material of conductorD. all of the above |
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Answer» Correct Answer - C |
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| 283. |
If voltage across a bulb rated 220 volt-100 watt drops by `2.5 %` of its value, the percentage of the rated value by which the power would decrease isA. `10%`B. `20%`C. `2.5%`D. `5%` |
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Answer» Correct Answer - D (d) Power consumed `P = (V^(2))/(R )`. For small variation `100 xx (Delta P)/(P) = 2 (Delta V)/(V) xx 100 = 2 xx 2.5 %` Therefore, power would decrease by `5%` |
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| 284. |
If voltage across a bulb rated 220 volt-100 watt drops by `2.5 %` of its value, the percentage of the rated value by which the power would decrease isA. 0.2B. 0.025C. 0.05D. 0.1 |
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Answer» Correct Answer - C `"Power", R=(V^(2))/(R)` As the resistance of the bulb is constant `therefore (DeltaP)/(P)=(2DeltaV)/(V)` `"% decrease in power"=(DeltaP)/(P)xx100=(2DeltaV)/(V)xx100` `2xx2.5%=5%` |
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| 285. |
An electron in the hydrogen atom circles around the proton with a speed of `2.18xx10^(6)`m/s in an orbit of radius `0.53Å` . The equivalent current isA. `1.048xx10^(-2)A`B. `1.048xx10^(-3)A`C. `1.048xx10^(-4)A`D. `1.058xx10^(-4)A` |
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Answer» Correct Answer - B `I=q/t=e/t=(e v)/(2 pi r)` `= (1.6xx10^(-19)xx2.18xx10^(6))/(6.28xx0.53xx10^(-10))` `=1.048 xx 10^(-3)A` |
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| 286. |
In a large building, there are 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and 1 heater of 1 kW. The voltage of electric mains is 220 V. The minimum capacity fo the main fuse of the building will be :A. `8 A`B. `10 A`C. `12 A`D. `14 A` |
| Answer» Correct Answer - C | |
| 287. |
This questions has Statement I and Statement II. Of the four choices given after the Statements, choose the one that best describes into two Statements. Statement-I : Higher the range, greater is the resistance of ammeter. Statement- II : To increase the range of ammeter, additional shunt needs to be used across it.A. Statement-I is true, Statement-II is true, Statement-II is the correct explanation of Statement-IB. Statement-I is true, Statement-II is true, Statement-II is not correct explanation of Statement -IC. Statement-I is true, Statement-II is false.D. Statement-I is false, Statement-II is true. |
| Answer» Correct Answer - D | |
| 288. |
This questions has Statement I and Statement II. Of the four choices given after the Statements, choose the one that best describes into two Statements. Statement-I : Higher the range, greater is the resistance of ammeter. Statement- II : To increase the range of ammeter, additional shunt needs to be used across it.A. Statement-1 is true, Statement-2 is True, Statement-2 is a correct explanation for Statement-1B. Statement -1 is True, Statement-2 is True, Statement -2 is NOT the correct explanation for Statement-1.C. Statement-1 is True, Statement-2 is False.D. Statement-1 is False, Statement-2 is True. |
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Answer» Correct Answer - D (d) Statements I is false and statement II is true. For ammeter, shunt resistance, `S = (IgG)/(I-Ig)` Therefore for I to increase, S should decrease, So additional S can be connected across it . |
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| 289. |
This questions has Statement I and Statement II. Of the four choices given after the Statements, choose the one that best describes into two Statements. Statement-I : Higher the range, greater is the resistance of ammeter. Statement- II : To increase the range of ammeter, additional shunt needs to be used across it.A. Statement-1 is true, Statement-2 is false.B. Statement-1 is false, Statme-2 is true.C. Statement-1 is true, Statement-2 is true, Statement-2 is the correct explanations of statement-1.D. Statement-1 is true, Statement-2 is true, Statement-2 is not the correct explanations of statement-1. |
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Answer» Correct Answer - B Statement -I(R) (False) `I=I+G/R (ddotO)/(cancel0)` If `R(R)` More `I(R)` Less Statement -II True Addition shunt in parallel decreases the resistance, |
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| 290. |
The value of `i_1//i_2` for a given diagram is A. `(P+Q)/(R-S)`B. `(R+S)/(P+Q)`C. `(P+Q)/(R+S)`D. `(R+S)/(P-Q)` |
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Answer» Correct Answer - B `(P+Q)i_(1)=(R+S)i_(2) rArr (i_(1))/(i_(2)) =(P+Q)/(R+S)` |
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| 291. |
Four wires AB , BC , CD , DA of resistance 4 ohm each and a fifth wire BD of resistance 8 ohm are joined to form a rectangle ABCD of which BD is a diagonal. The effective resistance between the points A and B isA. 24 ohmB. 16 ohmC. `(4)/(3)` ohmD. `(8)/(3)` ohm |
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Answer» Correct Answer - D |
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| 292. |
The resistivity of iron is `1 xx 10^(-7)` ohm -m. The resistance of a iron wire of paritcular length and thickness is 1 ohm. If the length and the diameter of wire both are doubled, then the resistivity in ohm-m will beA. `1 xx 10^(-7)`B. `2 xx 10^(-7)`C. `4 xx 10^(-7)`D. `8 xx 10^(-7)` |
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Answer» Correct Answer - A (a) Resistivity of some material is its intrinsic porterty and is constant at particular temperature. Resistivity does not depend upon shape. |
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| 293. |
The resistivity of iron is `1 xx 10^(-7)` ohm -m. The resistance of a iron wire of particular length and thickness is 1 ohm. If the length and the diameter of wire both are doubled, then the resistivity in ohm-m will beA. `1 xx 10^(-7)`B. `2 xx 10^(-7)`C. `4 xx 10^(-7)`D. `8 xx 10^(-7)` |
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Answer» Correct Answer - A |
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| 294. |
The intensity of radiation emitted by the sun has its maximum value at a wavelength of 510 nm and that emitted by the North star has the maximum value at 350 nm. If these stars behave like black bodies, then the ratio of the surface temperatures of the sun and the north star isA. `1.46`B. `0.69`C. `1.21`D. `0.083` |
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Answer» Correct Answer - B |
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| 295. |
In producing chlorine through electrolysis `100 W` power at `125 V` is being consumed. How much chlorine per min is liberated ? `ECE` of chlorine is `0.367 xx 10^(6) kg//C`A. `1.76 xx 10^(-3) kg`B. `9.67 xx 10^(-3) kg`C. `17.61 xx 10^(-3) kg`D. `3.67 xx 10^(-3) kg` |
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Answer» Correct Answer - C (c ) Mass of the substance deposited at the cathode `m = zit = z ((W)/(V)) t` `= 0367 xx 10^(-6) xx (100 xx 10^(3))/(125) xx 60 = 17.6 xx 10^(-3) kg` |
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| 296. |
A steady current of `1.5 A` flows through a copper voltameter for 10 min. If the electrochemical equivalent of copper is `30 xx 10^(-5) gC^(-1)`, the mass of copper deposited on the electrode will beA. 0.27 gmB. 0.40gmC. 0.50gmD. 0.67gm |
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Answer» `m=Zit=(30xx10^(-5))(1.5)(10xx60)` `=0.27gm` |
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| 297. |
A cell can be balanced against `110 cm` and `100 cm` of potentiometer wire, respectively with and without being short circuited through a resistance of `10 Omega`. Its internal resistance isA. `1.0Omega`B. `0.5Omega`C. `2.0Omega`D. zero |
| Answer» Correct Answer - A | |
| 298. |
An electric kettle has two heating coils. when one coil is used, water in the kettle boils in 5 minutes, while when second coil is used, same water boils in 10 minutes. If the two coils, connected in parallel are used simultaneously.the same water will boil in timeA. 9 min 20 secB. 5 minC. 7 min 30 secD. 2 min 30 sec |
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Answer» Correct Answer - A (a) In parallel `(1)R_(P) = (1)/(t_(1)) + (1)/(t_(2)) = t_(P) = (t_(1) t_(2))/(t_(1) + t_(2))` `= (5 xx 10)/(5 + 10) = (50)/(15) = 3.33 m i n = 3 m i n 20 sec` |
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| 299. |
In an electric kettle, water boils in 10 minutes after the kettle is switched on. With the same supply voltage if the water is to be boiled in 8 minutes, should the length of the heating elemnet be increased or decreased ? Explain . |
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Answer» For a given supply voltage, heat produced in time t is `H = V^(2)/R t = V^(2)/(rho l//A) t = (V^(2)At)/(rho l)` i.e., `H prop (t)/(1)` `:. H_(1)/H_(2) = t_(1)/t_(2) xx l_(2)/l_(1)` As `H_(1) = H_(2)`, so `1 = t_(1)/t_(2) xx l_(2)/l_(1)` or `l_(2)/l_(1) = t_(2)/t_(1) = 8/10 lt 1 or l_(2) lt l_(1)` It means the length of the heating wire should be decreased. |
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| 300. |
Assertion : If three identical bulbs are connected in series as shown in figure then on closing the switchs. Bulb `C` short circuited and hence illumination of bulbs `A` and `B` decreases. Reason : Voltage on `A` and `B` decreases A. both A and B will glow more brightlyB. both A and B will glow less brightly than beforeC. A will glow less brightly and B more brightlyD. None of the bulbs will glow |
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Answer» Correct Answer - C Bulbs B and C are connected in parallel. Suppose, voltage across A and B is same. If bulb C is fused, bulb B will work `P_(B)=(V^(2))/(R_(B))impliesP_(A)=(V^(2))/(R_(A))` `R=(R_(B)R_(C))/(R_(B)+R_(C))` `because " " R_(B) lt R_(A) therefore P_(B) gt P_(A)` |
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