Three identical cells , each having an `emf 1.5 V` and a constant internal resistance `2.0 omega`, are connected in series with a `4.0 omega resistor R`, first as in circuit (i) , and second as in circuit (ii) . Then ( power in R in circuit (i))/( Power in R in circuit (ii)) = A. `9.0`B. `7.2`C. `1.8`D. `3.0`

Three identical cells , each having an `emf 1.5 V` and a constant inte

1.	Three identical cells , each having an `emf 1.5 V` and a constant internal resistance `2.0 omega`, are connected in series with a `4.0 omega resistor R`, first as in circuit (i) , and second as in circuit (ii) . Then ( power in R in circuit (i))/( Power in R in circuit (ii)) = A. `9.0`B. `7.2`C. `1.8`D. `3.0`
Answer» Correct Answer - A Power `P = I^(2)R = ((V)/( R + 3 r ))^(2) R or P prop V^(2)` Power ratio `= ((V_(1))/(V_(2)))^(2) = (( 4.5)/( 1.5))^(2) = 3^(2) = 9 `

Discussion

No Comment Found

Related InterviewSolutions

How many calories of heat will be approximately developed in a `210 W` electric bulb in `5 min`?A. `15,000`B. `1050`C. `63,000`D. `80,000`
A constant voltage is applied between the two ends of a uniform metallic wire. Some heat is developed in it. The heat developed is doubled ifA. both the lengths and radius of the wire are halvedB. both the length and radius of the wire are doubledC. the radius of the wire is doubledD. the length of the wire is doubled
Two electric bulbs , rated for the same voltage , have powers of `200 W and 100 W`, respectively. If their resistances are `r_(1) and r_(2)` , respectively , thenA. ` r_(1) = 2 r_(2)`B. ` r_(2) = 2 r_(1)`C. ` r_(2) = 4 r_(1)`D. ` r_(1) = 4 r_(2)`
In figure circuit section `AB` absorbs energy at the rate of `5.0 W` when a current` i =1.0A` passes through it in the indicated direction.(a) What is the potential difference between points `A` and `B`? (b) Emf device `X` does not have internal resistance. What is its emf? (c) What is its polarity (the orientation of its positive and negative terminals)? A. `24 V`B. `32 V`C. 48 V`D. `12 V`
A heating coil is rated `100 W , 200 V`. The coil is cut in half and two pieces are joined in parallel to the same source . Now what is the energy `( "in" xx 10^(2) J)` liberated per second?
Three identical resistors are connected in series . When a certain potential difference is applied across the combination , the total power would be dissipated is `27 W`. How many times the power would be dissipated if the three resistors were connected in parallel across the same potential difference ?
The three resistance of equal value are arranged in the different combination shown below. Arrange them in increasing order of power dissipation.(I) (II) (IV) A. `III lt II lt IV lt I`B. `II lt III lt IV lt I`C. `I lt IV lt III lt II`D. `I lt III lt II lt IV`
Three `10 Omega , 2 W` resistors are connected as in Fig. `7.34`. The maximum possible voltage between points `A and B` without exceeding the power dissipation limits of any of the resistors is A. `5 sqrt(3) V`B. `3 sqrt(5) V`C. `15 V`D. ` (5)/(3) V`
An ideal gas is filled in a closed rigid and thermally insulated container. A coil of `100Omega` resistor carrying current 1 A for 5 minutes supplies heat to the gas. The change in internal energy of the gas isA. `10 kJ`B. `30 kJ`C. `20 kJ`D. `0 kJ`
If in the circuit shown in Fig.`7.55`, power dissipation is `150 W` , then find the value of `R ( "in" Omega)`.

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment