12th Physics || सेल के आंतरिक प्रतिरोध Internal Resistance of Cell विद्युत धारा Ch 3 L-6 | Gopal Sir

Cells A and B and a galvanometer G are connected to a side wire OS by two sliding contacts C and D as shows in Fig. 6.17 . The slide wire is 100 cm long and has a resistance of 12 Omega . With OD = 75 cm , the galvanometer gives no deflections when OC is 50 cm . If D is moved to touch the end of wire S , the value of OC for which the galvanometer shows no deflection is 62.5 cm . The emf of cell B is 1.0 V . Calculate (i) the potential difference across O and D when D is at 75 cm mark from O (ii) the potential difference across OS when D touches S (iii) internal resistance of cell A (iv) the emf of cell A

(a) When a cell sends current through a resistance R_(1) for time t , the heat produced in the resistor is Q . When the same cell sends current through another resistance R_(2) for time t the heat porduced is again Q . Find internal resistance of the cell. (b) An electric kettle has coil A is swithched on, the water boils in 10min. and when coil b is switched on the water boils in 20min . Calculate the time taken by the water to boil if the coils connected in (i) series and (ii) parallel are swithched on. (c) The emf of battery E in the circuit shown in the figure is 15V and internal resistance 0.5ohm (i) What is the current drown from the battery? (ii) How much power is consumed in 6 ohm resistance? (d) A 500W heating unit is designed to opreate from a 115V line. (i) By what percentage will its heat output drop if the line voltage drops to 110V . Assuming no change in resistance? (ii) Taking variation of resistance with temperature into account. would the actual heat output drop be larger or smaller than case(i) (e) If emf of the cell is 1.8V and its internal resistance 2//3 Omega for the circuit shown in the figure what is the (i) current in 3 ohm resistance? (ii) Power consumed by the circuit from the battery? (i) for what value of R , power in R is maximum? .

In the arrangement shown in figure when the switch S_2 is open, the galvanometer shown no deflection for l=L//2 . When the switch S_2 is closed, the galvanometer shown no deflection for l=5L//12 . The internal resistance (r) of 6V cell, and the emf E of the other battery are respectively

Figure 6.13 shows a 2.0 V potentiometer used for the determination of internal resistance of a 1.5 V cell. The balance point of the cell in open circuit is 76.3 cm . Whan a resistor of 9.5 Omega is used in the external circuit of the cell, the balance point shifts to 64.8 cm , length of the potentiometer. Dentermine the internal resistance of the cell.

A cell of emf 12 V and internal resistance 6Omega is connected in parallel with another cell of emf 6 V ad internal resistance 3Omega , such that the positive of the first cell joins the positive to the second cell and similarly the negative of first cell joins the negative of the second cell. A bulb of filament resistance 14Omega is connected across the combination. The power delivered to be bulb is

A potentiometer arrangement is shows in Fig. 6.62 . The driver cell has emf e and internal resistance r . The resistance of potentiometer wire AB is R.F is the cell of emf e//3 and internal resistance r//3 . Balance point (J) can be obtained for all finite value of

[" 28.To get maximum current in a resistance of "3" ohm,one can use n rows of "m" ."],[" cells (connected in series) connected in parallel.If the total number of cells is "],[24" and the internal resistance of a cell is "0.5" ohm,then "],[[" 1) "m=12,n=2," 2) "n=3,m=8," 3) "m=2,n=12," 4) "m=6,n=4]]