Advertisements
Advertisements
प्रश्न
Answer the following question.
Two bulbs are rated (P1, V) and (P2, V). If they are connected (i) in series and (ii) in parallel across a supply V, find the power dissipated in the two combinations in terms of P1 and P2.
उत्तर
Given Bulbs are rated as (P1, V) and (P2, V) respectively
The resistance of 1st bulbs `R_1 = V^2/P_1`
The resistance of 2nd bulbs `R_2 = V^2/P_2`
(i) When both are connected in series with a power supply of voltage V. As both the bulbs are in series connection hence both will have the same amount of current flowing through them.
i = `V/(R_1 + R_2) = V/(V^2/P_1 + V^2/P_2) = 1/V((P_1P_2)/(P_1 + P_2))`
Power dissipated in the circuit
`P_d = i^2(R_1 + R_2) = 1/V^2((P_1P_2)/(P_1 + P_2))^2(V^2/P_1 + V^2/P_2)`
`P_d = (P_1P_2)/(P_1 + P_2)`
(ii) When both are connected in parallel In this case, both bulbs will get the same voltage supply. Hence, power dissipated
`P_d = V^2/R_1 + V^2/R_2 = V^2(P_1/V^2 + P_2/V^2)`
`P_d = P_1 + P_2`.
संबंधित प्रश्न
Two metallic wires, P1 and P2 of the same material and same length but different cross-sectional areas, A1 and A2 are joined together and connected to a source of emf. Find the ratio of the drift velocities of free electrons in the two wires when they are connected (i) in series, and (ii) in parallel.
100 cells each of emf 5 V and internal resistance 1 Ω are to be arranged so as to produce maximum current in a 25 Ω resistance. Each row contains equal number of cells. The number of rows should be ______.
Choose the correct alternative.
Five dry cells each of voltage 1.5 V are connected as shown in the diagram
What is the overall voltage with this arrangement?
Two cells of 1.25 V and 0.75 V are connected in series with anode of one connected to anode of the other. The effective voltage will be ______.
If two bulbs of wattages 25 W and 100 W respectively each rated by 220 V are connected in series with the supply of 440 v·then which bulb will fuse?
When cells are connected in parallel, then ______
Two cells of emf’s approximately 5V and 10V are to be accurately compared using a potentiometer of length 400 cm.
Two cells of emfs E1 and E2 and internal resistances r1 and r2 respectively are connected in parallel as shown in the figure. Deduce the expression for the
- equivalent emf of the combination
- equivalent internal resistance of the combination
- potential difference between the points A and B.
The equivalent resistance of series combination of two resistors is 's'. When they are connected in parallel, the equivalent resistance is 'p'. If s = np, then the minimum value for n is ______. (Round off to the Nearest Integer)
A 60 Ω resistor, a 1.0 H inductor and a 4 μF capacitor are connected in series to an ac supply generating an emf e = 300 sin (500t) V. Calculate:
- impedance of the circuit.
- peak value of the current flowing through the circuit.
- phase difference between the current and the supply voltage.
