Current Electricity PYQs Set 6 (PDF)

Set 6 of 21 · Questions 151-180 of 612

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Mere Teacher · Previous Year Questions NEET Physics · Current Electricity · Set 6 (Q151-180)
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151. $In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60 W bulb for use in India is R, the resistance of a 60 W bulb for use in USA will be$ (1) $R$ (2) $2 R$ (3) $R /4$ (4) $R /2$ 152. $A metal wire is subjected to a constant potential difference. When the temperature of the metal wire increases, the drift velocity of the electron in it$ (1) $increases, thermal velocity of the electron increases$ (2) $decreases, thermal velocity of the electron increases$ (3) $increases, thermal velocity of the electron decreases$ (4) $decreases, thermal velocity of the electron decreases.$ 153. $A battery consists of a variable number n of identical cells (having internal resistance r each) which are connected in series. The terminals of the battery are short-circuited and the current I is measured. Which of the graphs shows the correct relationship between I and n? [NEET 2018]$ (1) (2) (3) (4) 154. $A 5^{o} C rise in temperature is observed in a conductor by passing acurrent. When the current is doubled the rise in temperature will be approximately$ (1) $2 0^{o} C$ (2) $1 6^{o} C$ (3) $1 0^{o} C$ (4) $1 2^{o} C$ 155. $A galvanometer of resistance has 50 divisions on its scale and has sensitivity of 20 μA / division. It is to be converted to a voltmeter with three ranges, of 0 - 2 V, 0 - 10 V and 0 - 20 V . The appropriate circuit to do so is:$ (1) (2) (3) (4) 156. $A resistance of 20Ω is connected in the left gap of a metre bridge and an unknown resistance greater than 20Ω is connected in the right gap. When these resistances are interchanged, the balance point shifts by 20 cm . the unknown resistance is$ (1) $25Ω$ (2) $40Ω$ (3) $35Ω$ (4) $30Ω$ 157. $Though the electron drift velocity is small and electron charge is very small, a conductor can carry an appreciably large current because$ (1) $electron number density depends on temperature$ (2) $electron number density is very large$ (3) $relaxation time is small$ (4) $drift velocity of electron is very large.$ 158. $The diameter of a sphere is measured using a vernier caliper whose 9 divisions of main scale are equal to 10 divisions of vernier scale. The shortest division on the main scale is equal to 1 mm . The main scale reading is 2 cm and second division of vernier scale coincides with a division on main scale. If mass of the sphere is 8.635 g, the density of the sphere is:$ (1) $2.0 g / cm^{3}$ (2) $1.7 g / cm^{3}$ (3) $2.2 g / cm^{3}$ (4) $2.5 g / cm^{3}$ 159. $A resistance of 2 Ω is connected across one gap of a meter-bridge (the length of the wire is 100 cm) and an unknown resistance, greater than 2 Ω, is connected across the other gap. When these resistances are interchanged, the balance point shifts by 20 cm. Neglecting any corrections, the unknown resistance is$ (1) $3$ (2) $4$ (3) $5$ (4) $6$ 160. $A metal rod of length 10 cm and a rectangular cross-section of 1 cm \times \frac{1}{2} cm is connected to a battery across opposite faces. The resistance will be$ (1) $maximum when the battery is connected across 10 cm \times 1 cm faces$ (2) $same irrespective of the three faces$ (3) $maximum when the battery is connected across 1 cm \times \frac{1}{2} cm faces$ (4) $maximum when the battery is connected across 10 cm \times \frac{1}{2} cm faces.$ 161. $In a metallic conductor, under the effect of applied electric field, the free electrons of the conductor$ (1) $Drift from higher potential to lower potential$ (2) $Move with the uniform velocity throughout from lower potential to higher potential$ (3) $Move in the straight line paths in the same direction$ (4) $Move in the curved paths from lower potential to higher potential$ 162. $A copper wire of length 10m and radius (10^{- 2} / π) m has electrical resistance of 10Ω . The current density in the wire for an electric field strength of 10 (V / m) is [NEET 2022]$ (1) $10^{4} A / m^{2}$ (2) $10^{6} A / m^{2}$ (3) $10^{- 5} A / m^{2}$ (4) $10^{5} A / m^{2}$ 163. $A current of 5 A passes through a copper conductor (resistivity) = 1.7 \times 10^{- 8}) of radius of cross-section 5 mm . Find the mobility of the charges if their drift velocity is 1.1 \times 10^{- 3} ms .$ (1) $1.8 m^{2} / Vs$ (2) $1.5 m^{2} / Vs$ (3) $1.3 m^{2} / Vs$ (4) $1.0 m^{2} / Vs$ 164. $With the help of potentiometer, we can determine the value of emf of a given cell. The sensitivity of the potentiometer is (A) directly proportional to the length of the potentiometer wire (B) directly proportional to the potential gradient of the wire (C) inversely proportional to the potential gradient of the wire (D) inversely proportional to the length of the potentiometer wire Choose the correct option for the above statements:$ (1) $B and D only$ (2) $A and C only$ (3) $A only$ (4) $C only$ 165. $An electric bulb rated 50 W - 200 V is connected across a 100 V supply. The power dissipation of the bulb is:$ (1) $25 W$ (2) $12.5 W$ (3) $50 W$ (4) $100 W$ 166. $The current in the primary circuit of a potentiometer is 0.2 A. The specific resistance and cross-section of the potentiometer wire are 4 \times 1 0^{-7} ohm meter and 8 \times 1 0^{-7} m^{2} respectively. The potential gradient will be equal to:$ (1) $1 V/ m$ (2) $0.5 V/m$ (3) $0.1 V/m$ (4) $0.2 V/m$ 167. $Which of the following acts as a circuit Which of the following acts as a circuit protection device?$ (1) $fuse$ (2) $conductor$ (3) $inductor$ (4) $switch$ 168. $A wire of resistance R_{1} is drawn out so that its length is increased by twice of its original length. The ratio of new resistance to original resistance is:$ (1) $9 : 1$ (2) $1 : 9$ (3) $4 : 1$ (4) $3 : 1$ 169. $The resistance of a conductor at 150C is 16Ω and at 1000C is 20Ω . What will be the temperature coefficient of resistance of the conductor?$ (1) $0.01 0^{0} C^{- 1}$ (2) $0.03 3^{0} C^{- 1}$ (3) $0.00 3^{0} C^{- 1}$ (4) $0.04 2^{0} C^{- 1}$ 170. $An ammeter of resistance ' R' gives a full scale deflection when a current of 2 A passes through. it. If it is to measure maximum current of 10 A, the required shunt is$ (1) $\frac{R}{4}$ (2) $R$ (3) $2 R$ (4) $\frac{R}{2}$ 171. $A battery with EMF E and internal resistance r is connected across a resistance R . The power consumption in R will be maximum when:$ (1) $R = 2 r$ (2) $R = r /2$ (3) $R = r$ (4) $R = 2 r$ 172. $In good conductors of electricity, the type of bonding that exists is$ (1) $metallic$ (2) $vander Waals$ (3) $ionic$ (4) $covalent.$ 173. $Two equal resistances when connected in series to a battery, consume electric power of 60 W . If these resistance are now connected in parallel combination to the same battery, the electric power consumed will be:$ (1) $60 W$ (2) $240 W$ (3) $120 W$ (4) $30 W$ 174. $By what percentage will the illumination of the lamp decrease if the current drops by 20 % ?$ (1) $46 %$ (2) $26 %$ (3) $36 %$ (4) $56 %$ 175. $To measure the internal resistance of a battery, potentiometer is used. For R = 10Ω, the balance point is observed at l = 500 cm and for R = 1Ω the balance point is observed at l = 400 cm . The internal resistance of the battery is approximately:$ (1) $0.2Ω$ (2) $0.3Ω$ (3) $0.4Ω$ (4) $0.1Ω$ 176. $The time required to raise the temperature of 3 liter of water from 0^{\circ} C to 80^{\circ} C by a heater operated under 200 V having resistance of 50Ω is [specific heat capacity of water is 4200 J kg^{- 1} K^{- 1}] [density of water = 1000 kg / m^{3}]$ (1) $12 min$ (2) $18 min$ (3) $21 min$ (4) $24 min$ 177. $Which of the following graphs correctly represents the variation of heat energy (U) produced in a metallic conductor in a given time as a function of potential difference (V) across the conductor?$ (1) (2) (3) (4) 178. $In a potentiometer experiment the balancing length with a cell is 560 cm . When an external resistance of 10Ω is connected in parallel to the cell, then the balancing length changes by 60 cm . Find the internal resistance of the cell.$ (1) $1Ω$ (2) $2Ω$ (3) $1.2Ω$ (4) $2.1Ω$ 179. $A wire 50 cm long and 1 m m^{2} in cross‐ section carries a current of 4 A when connected to a 2 V battery. The resistivity of the wire is$ (1) $4\times 1 0^{- 6} Ωm$ (2) $1\times 1 0^{- 6} Ωm$ (3) $2\times 1 0^{- 7} Ωm$ (4) $5\times 1 0^{- 7} Ωm$ 180. $In a potentiometer experiment, the balancing point with a cell is at a length 240 cm . On shunting the cell with a resistance of 2Ω, the balancing length becomes 120 cm . The internal resistance of the cell is$ (1) $1Ω$ (2) $4Ω$ (3) $0.5Ω$ (4) $2Ω$