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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.
| 1151. |
The value of current `I`, in the will be A. `9A`B. `12A`C. `13A`D. `19 A` |
| Answer» Correct Answer - c | |
| 1152. |
Wheaststone bridge is most sensitive when the resistance of all four arms areA. `R_(1)=R_(2)` and `R_(3)=R_(4)`B. `R_(1)=R_(2)=R_(3)=R_(4)`C. `R_(1)+R_(2)=R_(3)+R_(4)`D. `R_(1)-R_(2)=R_(3)-R_(4)` |
| Answer» Correct Answer - B | |
| 1153. |
If three cell are connected in parallel then equivalent emf……. and equivalent internal resistance is ….. |
| Answer» Correct Answer - `E_(eq) = ((E_(1))/(r_(1)) +(E_(2))/(2_(2)) +(E_(3))/(r_(3)))/((1)/(r_(1)) + (1)/(r_(2)) + (1)/(r_(3))) = (sum_(t = 1)^(1) E_(1)//r_(1))/(sum_(t= 1)^(2) 1//r_(1)) : r_(eq) = (r_(1)r_(2)r_(3))/(r_(1)r_(2) + r_(2)r_(2) + r_(3)r_(1))` | |
| 1154. |
The medium between the plate of battery offers some resistance to the flow of charge within th e battery this given rise to …… of the cell |
| Answer» Correct Answer - internal resistance | |
| 1155. |
Which of the following instruments is generally used with a galvanometer to show null reading ?A. an ammeterB. a voltmeterC. a voltameterD. a metre bridge |
| Answer» Correct Answer - D | |
| 1156. |
Resistivity is the property of the ……. and it depends opon the ….. of unbalance and ….. |
| Answer» Correct Answer - substance : nature of material : temperature | |
| 1157. |
The rate of flow of electric charge isA. electric currentB. voltageC. powerD. resistance |
| Answer» Correct Answer - A | |
| 1158. |
How can you keep a constant current inside a conductor? |
| Answer» A constant current can be kept inside a conductor by maintaing a constant potential differnce across the two ends of conductor. | |
| 1159. |
The electric current is aA. scalar quantityB. vector quantityC. unitlessD. none of these |
| Answer» Correct Answer - A | |
| 1160. |
When a steady current passes through a cylindrical conductor, is there an electric field inside the conductor? |
| Answer» Yes. A steady current can flow in a cylindrical conductor if electric force is acting on free electrons which makes the electrona to move in a particular direction. It is possible due to electric field within the conductor. | |
| 1161. |
If the elctric current is passed through a nerve, the man is excited, why? |
| Answer» The man is excited due to transfer of electric energy to his body. | |
| 1162. |
If the elctric current is passed through a nerve, the man is excited, why?A. Begins to laughB. Begins to weepC. Is excitedD. Becomes insensitive to pain |
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Answer» Correct Answer - C |
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| 1163. |
If an electron has an initial velocity in a direction different from that of an electric field, then the path of the electron isA. parabolaB. circleC. ellipseD. straight line |
| Answer» Correct Answer - D | |
| 1164. |
If an electric current is passed through the nerve, the manA. is excitedB. begins to weepC. begins to laughD. becomes insensitive to pain |
| Answer» Correct Answer - A | |
| 1165. |
S.I. unit of current is :-A. ampereB. stat ampereC. coulombD. henry |
| Answer» Correct Answer - A | |
| 1166. |
In vacuum tubes, the flow of electricity is due to the electrons coming out ofA. ionsB. cathodeC. anodeD. filament |
| Answer» Correct Answer - B | |
| 1167. |
A water heater has a well insulated vertical cylindrical container of radius a in which water is filled to a height `h`. A resistor made of an allow is used to heat the water in the tank from a temperature `theta_(1)` to `theta_(2) (gt theta_(1))` in a time interval `Deltat`. The resistor wire has cross sectional radius b and its alloy material has resistivity `rho`. Calculate the length of the resistor wire. Density and specific heat capacity of water are `d and s` respectively. The power source connected to the resistor has emf `epsilon`. |
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Answer» Correct Answer - `(epsilon^(2)b^(2))/(rhohsa^(2))(Deltat)/((theta_(2)-theta_(1)))` |
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| 1168. |
In the circuit shown in the fig., `R_(1): R_(2) : R_(3) = 4 : 1 : 2`. (a) Will the current through `R_(1)` increase or decrease when a new resistance `R_(4)` is added in parallel to `R_(2)` ? (b) Change in current through `R_(1)` when `R_(4)` is added is found to be `0.2 A`. Calculate the current through `R_(4)`. |
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Answer» Correct Answer - (a) Increase (b) `I_(4) = 1.4 A` |
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| 1169. |
Two identical voltmeters and two identical ammeter are connected to a battery of negligible resistance shown in the figure. The readings of devices are follows Reading of Ammeter `A_(1) = 200 muA` Reading of voltmeter `V_(2) = 2` volt Reading of voltmeter `V_(1) = 100` volt Choose the correct option(s)A. Reading of ammeter `A_(2)` is `196 muA`B. Resistance of voltmeter is `0.5 M Omega`C. Resistance of ammeter is `10.2 kOmega`D. Current passing through voltmeter `V_(2)` is `4 muA` |
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Answer» Correct Answer - A::B::C::D |
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| 1170. |
In the circuit shown in figure all resistances are identical (each equal to R) and the cell has an emf of `V_(0)`. The three voltmeters `V_(1), V_(2) and V_(3)` are identical and are nearly ideal. (a) find the reading of the voltmeter `V_(1)` when switch ‘S’ is open. (b) find the reading of the voltmeter `V_(1)` after the switch is closed |
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Answer» Correct Answer - (a) `(V_(0))/(6)` (b) `(2V_(0))/(9)` |
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| 1171. |
In the circuit shown in figure a current `I = 600 muA` enters through A and leaves through B. Reading of the identical voltmeters `V_(1) and V_(2)` are `20 V and 30 V `respectively. find R. |
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Answer» Correct Answer - `50 k Omega` |
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| 1172. |
In the circuit shown in the figure, two resistors `R_(1) and R_(2)` have been connected in series to an ideal cell. When a voltmeter is connected across `R_(1)` its reading is `V_(1) = 4.0` volt and when the same voltmeter is connected across `R_(2)` its reading is `V_(2) = 6.0` volt. The reading of the voltmeter when it is connected across the cell is `V_(3) = 12.0` volt. Find the actual across `R_(1)` in the circuit. |
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Answer» Correct Answer - 4.8 V |
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| 1173. |
An ohm-meter is a device that measures an unknown resistance. A simple ohm-meter can be constructed using a galvanometer as shown in the figure. The cell used in the circuit has emf `E = 20` volt. The full scale deflection current and resistance of the galvanometer are `2 mA` and `20 Omega` respectively. `R_(0)` is a fixed resistance and R is the unknown resistance whose value is directly given by the galvanometer scale. The galvanometer scale is shown in figure. When an unknown resistance `R` is placed in the circuit, the pointer deflects by `theta = 90^(@)`. Find R. |
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Answer» Correct Answer - `3333 Omega` |
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| 1174. |
Three identical capacitors, each of capacitance C are connected in series. The capacitors are charged by connecting a battery of emf V to the terminals (a and d) of the circuit. Now the battery is removed and two resistors of resistance R each are connected as shown. find the heat dissipated in one of the resistors |
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Answer» Correct Answer - `(2)/(27) CV^(2)` |
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| 1175. |
To enhance the sensitivity, an Ammeter is to be designed with two kinds of graduation on its scale — 0 to `10 A` and 0 to 1 A. for that a galvanometer of resistance `50 Omega` and full scale deflection current 1 mA was used along with two resistances `R_(1) and R_(2)` as shown. Either of `T_(1) or T_(2)` is to be used as negative terminal of the Ammeter. (a) When measuring a current of the order of `0.1 A`, which shall be used as negative terminal — `T_(1) or T_(2)` ? (b) find the values of `R_(1) and R_(2)`. |
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Answer» Correct Answer - (a) `T_(2)` (b) `R_(1)=(5)/(999)Omega` `R_(2)=(5)/(111)Omega` |
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| 1176. |
Shows on a plot of current `I` through the cross section of the wire over a time intenal of `14 s` Find the amount of charge that passes through the wire (i) during `10 s` (ii) during `14s` |
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Answer» Correct Answer - `50C` Amount of charge that flow in `10s` = area (OABD) under the `I - t` graph = Area of Delta OAE+ area ABCD `= (5xx4)/(2) + 5xx (10 - 4) = 10+ 30 = 40 C` (ii) Amount of charge that flow in `14s` = area OABC = Area OABD+ area DBC `= 40 + 5xx (14 - 10)//2 = 50C` |
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| 1177. |
An electric current of `20 mu A` appears in a discharege tube if the discharge current is due to flow of equal number of electrons and protons then how many electrons flow across a cross-section of the tube in `2` minutes |
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Answer» Correct Answer - `7.5 xx 10^(15)` Total charge flowing in two minutes `q = It = (20 xx 10^(-6)A) xx (2 xx 60s) = 24 xx 10^(-4) C` Charge flowing due to electron `= (24 xx 10^(-4))/(2) = 12 xx 10^(-4)C` No of electron flowing across-section of a tube is `2` minutes is `n= (12 xx 10^(-4))/(1.6 xx 10^(-19)) = 7.5 xx 10^(15)` |
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| 1178. |
In a region `10^(19) prop`-particles and `10^(19)` protons move to the left, while `10^(19)` electrons moves to the right per second. The current isA. 3.2 A towards leftB. 3.2 A towards rightC. 6.4 A towards leftD. 6.4 A towards right |
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Answer» Correct Answer - C An `alpha` - particle has a charge equal to 2 protons. Motion of `alpha`- particle to the left, motion of proton towards left and motion of electrons towards right, all will produce conventional current towards left. The total current will be `i=10^(19)xx(2xx1.6xx10^(-19))+10^(19)xx(1.6xx10^(-19))+10^(19)xx(1.6xx10^(-19))=6.4 A` |
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| 1179. |
A flow of `10^(7)` electrons per second in a conducting wire constitutes a current ofA. `1.6xx10^(-26)A`B. `1.6xx10^(-12)A`C. `1.6xx10^(12)A`D. `1.6xx10^(26)A` |
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Answer» Correct Answer - B `I=(q)/(t)=(n e)/(t)=(10^(7)xx1.6xx10^(-19))/(1)` `=1.6xx10^(-12)A` |
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| 1180. |
In a region `10^(19) prop`-particles and `10^(19)` protons move to the left, while `10^(19)` electrons moves to the right per second. The current isA. 3.2 A towards leftB. 6.4 A towards leftC. 9.6 A towards leftD. 6.4 A towards right |
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Answer» Correct Answer - B Electric current due to flow of `10^(19) alpha-`particles towards left is , `I_(1)=2 n_(1)e=2xx10^(19)xxe` Electric current due to flow of `10^(19)` electrons towards left is , `I_(2)=10^(19)xxe` Electric current due to flow of `10^(19)` protons towards left is , `I_(3)=10^(19)xxe` Thus, total electric current is , `I=I_(1)+I_(2)+I_(3)=4e xx 10^(19)` `=4xx1.6 xx 10^(-19)xx10^(19)=6.4` A |
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| 1181. |
In the question find the resistacnce between points 1-3. A. `3/4R`B. `5/6R`C. `3/5R`D. `6/5R` |
| Answer» Correct Answer - A | |
| 1182. |
The equivalent resistance between `A` and `B` will be (in `Omega`) A. `2/7`B. `8`C. `4/3`D. `7/3` |
| Answer» Correct Answer - D | |
| 1183. |
The equivalent resistance between points A and B is A. `65/2Omega`B. `45/2Omega`C. `5/4Omega`D. `91/2Omega` |
| Answer» Correct Answer - B | |
| 1184. |
Six wires each of resistance r form a tetrahedron. The equivalent resistance between corners 1-2 and 1-3 are respectively A. `r/2,r/2`B. `r,r`C. `r/2,r`D. `r,r/2` |
| Answer» Correct Answer - A | |
| 1185. |
Consider an evacuated cylindrical chamber of hight h rigid conducting plates at the ends and an insulating curved surgace as shown in the figure. A number of spherical balls madeof a light weight and soft material and coagted with a conducting material are placed on the bottom plate. The balls have a radius `rltlth`. Now a high voltage source (HV) is connected across the conducting plates such that th ebottom plate is `at+V_(0)`and the top plate `at-V_(0)`. Due to their conducting surface the balls will get charged, will become equipotential with the plate and are repelled by it. The balls will eventually collide with the top plate, where the coefficient of reatitution can be taken to be zero due to the soft nature of the material of the balls. The electric field in the chamber can be considered to be considered to be that of a parallel plate capacitor. Assume tht there are no collisions between the balls and the interaction between them is negligible. (Ignore gravity) The average current in the steady state registered by the ammeter in the circuit will beA. proportional to `V_(0)^(2)`B. proportional to `V_(0)^(1//2)`C. proportional to the potential `V_(0)`D. zero |
| Answer» Correct Answer - A | |
| 1186. |
Consider an evacuated cylindrical chamber of hight h rigid conducting plates at the ends and an insulating curved surgace as shown in the figure. A number of spherical balls madeof a light weight and soft material and coagted with a conducting material are placed on the bottom plate. The balls have a radius `rltlth`. Now a high voltage source (HV) is connected across the conducting plates such that th ebottom plate is `at+V_(0)`and the top plate `at-V_(0)`. Due to their conducting surface the balls will get charged, will become equipotential with the plate and are repelled by it. The balls will eventually collide with the top plate, where the coefficient of reatitution can be taken to be zero due to the soft nature of the material of the balls. The electric field in the chamber can be considered to be considered to be that of a parallel plate capacitor. Assume tht there are no collisions between the balls and the interaction between them is negligible. (Ignore gravity) Which one of the following statements is correct ?A. The balls will execute simple harmonic motion between the two platesB. The balls will bounce back to the bottom plate carrying the opposite charge they went up withC. The balls will bounce back to the bottom plate carrying the same charge they went up withD. The balls will stick to the top plate and remain there |
| Answer» Correct Answer - B | |
| 1187. |
A galvanometer, having a resistance of `50 Omega` gives a full scale deflection for a current of `0.05 A`. The length in meter of a resistance wire of area of cross-section `2.97 xx 10^(-2) cm^(2)` that can be used to convert the galvanometer into an ammeter which can read a maximum of `5 A` current is (Specific resistance of the wire `5 xx 10^(-7) omega m`)A. 9B. 6C. 3D. 1.5 |
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Answer» Correct Answer - C (c ) `(i)/(i_(g)) = 1 + (G )/(S) implies (5)/(0.05) = 1 + (50)/(S)` `implies S = (50)/(99) = (rho xx l)/(A) implies l = (50)/(99) xx (2.97 xx 10^(-2) xx 10^(-4))/(5 xx 10^(-7)) = 3 m` |
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| 1188. |
The total electrical resistance between the points A and B of the circuit shown, is A. `9.23 Omega`B. `15 Omega`C. `30 Omega`D. `100 Omega` |
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Answer» Correct Answer - A In branch, (1) resistors are in series. `R_(1)=10+10+10=30 Omega` In branch (3), 20 and 20 are in series `therefore " " R_(3)=20+20=40 Omega` The equivalent circuit of (1), (2) and (3) branches are in parallel. `therefore (1)/(R_(eq))=(1)/(30)+(1)/(30)+(1)/(20)+(1)/(40)=(4+6+3)/(120)=(13)/(120)` `E_(eq)=(120)/(13)=9.23 Omega` |
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| 1189. |
An electric heater rated as (500 W and 200 V) raises the temperature of 1 kg water from `15^(@)C` to its boiling point in 15 min. the heat effeciency of the heater isA. 0.79B. 0.97C. 0.69D. 0.96 |
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Answer» Correct Answer - A Heat absorbed by water `=msDeltaT` Heat supplied by heater`=vlt=Pt` `therefore " " " Efficiency " =(msDeltaT)/(Pt)xx100` By putting given value, efficiency `~~ 79 %` |
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| 1190. |
Cell of emf 1 V is connected across a potentiometer, balancing length is 600 cm. What will be the balancing length for 25 V?A. 400 cmB. 600 cmC. 1500 cmD. 1200 cm |
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Answer» Correct Answer - C For a potentiometer `(E_(1))/(l_(1))=(E_(2))/(l_(2))=1500 cm` |
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| 1191. |
The resistance of iron wire is `10Omega` and `alpha=5xx(10^(-3))/( .^(@)C)`. If a current of 30A is flowing in it at `20^(@)C` keeping the potential difference across its length constant, if the temperature is incresed to `120^(@)C` what is the current flowing through that wire? |
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Answer» `alpha=(R_(120)-R_(20))/(R_(20)(120-20)),5xx10^(-3)=(R_(120)-10)/(10xx100)` `thereforeR_(120)=15Omega,but V=IR` Here V is constant Hence, `(I_(120))/(I_(20))=(R_(20))/(R_(120)),(I_(120))/(30)=(10)/(15),becauseI_(120)=20A` |
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| 1192. |
Temperature coefficient of resistance of platinum is `alpha=3.92xx10^(-3)K^(-1)` at `0^(@)C`. Find the temperature at which the increase in the resistance of platinum wire is `10%` of its value at `0^(@)C` |
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Answer» `R_(2)=(110R_(1))/(100)=1.1R_(1),alpha=3.92xx10^(-3)K^(-1)` `Deltat=(R_(2)-R_(1))/(R_(1)alpha)implies(1.1R_(1)-R_(1))/(R_(1)alpha)` `=(R_(1)(1.1-1))/(R_(1)alpha)=(0.1R_(1))/(R_(1)alpha)=(0.1)/(3.92xx10^(-3))` `Deltat=25.51^(@)C,t_(2)=25.51+20=45.51^(@)C` |
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| 1193. |
What is the equivalent resistance of the circuitA. `6Omega`B. `7Omega`C. `8Omega`D. `9Omega` |
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Answer» Correct Answer - C combination of resistors |
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| 1194. |
In the figure, each segment (side of small triangle) has resistance R and the wire used in the circumference of the circle has negligible resistance. find equivalent resistance between point O and A. |
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Answer» Correct Answer - `(R)/(4)` |
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| 1195. |
The temperature coefficient of resistance of platinum is `alpha=3.92xx10^(-3)K^(-1)` at `20^(@)C`. Find the temperature at which the increase in the resistance of platinum wire is `10%` of its value at `20^(@)C`A. `40.5^(@)C`B. `45.5^(@)C`C. `48.5^(@)C`D. `43.5^(@)C` |
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Answer» Correct Answer - B `Deltat=(R_(2)-R_(1))/(R_(1)alpha)` |
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| 1196. |
`AB and CD` are two resistance wires cut from a uniform long wire. Lengths of `AB and CD` are `L and 2L` respectively and resistance of AB is R. The two resistances are connected in parallel to a supply. P and Q are two points on the resistance AB such that `AP = QB = (L)/(3)`. Two conductors `PS and QT` are connected between two resistors such that no current flows through both the conductors. A resistance R is connected between points M and N as shown. Neglect resistance of PS and QT. (a) find the equivalent resistance of the circuit between X and Y. (b) Will there be any current in resistance connected across MN ? |
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Answer» Correct Answer - (a) `(62 R)/(99)` (b) Yes |
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| 1197. |
Four identical resistance are joined as shown in fig. the equivalent resistance between points A and B is `R_(1)` and that between A and C is `R_(2)`. Then ratio of `(R_(1))/(R_(2))` is A. `1:5`B. `3:4`C. `2:5`D. `1:2` |
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Answer» Correct Answer - B combination of resistors |
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| 1198. |
(a) In the circuit shown in figure, all resistances are identical when a `5 V` supply is connected across AB the current in branch CG is 3 mA. Find the effective resistancce if the circuit between A and B (b) Twelve equal resistances, each equal to R, are placed along the sides of a cube. Find equivalent resistance across. (i) Diagonally opposite points of the cube (ii) Diagonally opposite point on one face of the cube (iii) End points of a side of the cube. |
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Answer» Correct Answer - (a) `500 Omega` (b) (i) `(5R)/(6)` (ii) `(3R)/(4) (iii) `(7R)/(12)` |
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| 1199. |
The current – voltage characteristic of an electric device is as shown in figure (b). The device gets damaged if power dissipated in it exceeds 1 Watt. This device is connected to a dc source of variable emf (V) and a resistance `(R = 100 Omega)` in series. What is possible range of V for which the device remains operational (i.e. consumes some power) and safe. |
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Answer» Correct Answer - `20 V lt V lt 25 V` |
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| 1200. |
In the circuit shown in the fig the equivalent resistance between `a and b` is `R_(ab)` and the equivalent between `a and c` is `R_(ac)`. find the ratio `R_(ab) : R_(ac)`. |
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Answer» Correct Answer - `(1190)/(1189)` |
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