मराठी
महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता १२ वी

A voltmeter has a resistance of 100 Ω. What will be its reading when it is connected across a cell of emf 6 V and internal resistance 20 Ω? - Physics

Advertisements
Advertisements

प्रश्न

A voltmeter has a resistance of 100 Ω. What will be its reading when it is connected across a cell of emf 6 V and internal resistance 20 Ω? 

बेरीज

उत्तर

Terminal potential, V = `"E"/("R" + "r") xx "R" = 6/(100 + 20) xx 100 = 5`V

shaalaa.com
Potentiometer
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 9: Current Electricity - Very Short Answer

APPEARS IN

संबंधित प्रश्‍न

State the principle of working of a potentiometer.


Write two factors by which current sensitivity of a potentiometer can be increased.


On what factors does the potential gradient of the wire depend?


State the advantages of potentiometer over voltmeter.


In the given circuit, with steady current, calculate the potential drop across the capacitor and the charge stored in it.


(i) State the principle on which a potentiometer works. How can a given potentiometer be made more sensitive?

(ii) In the graph shown below for two potentiometers, state with reason which of the two potentiometers, A or B, is more sensitive.

In the given circuit in the steady state, obtain the expressions for (a) the potential drop (b) the charge and (c) the energy stored in the capacitor, C.


In the figure a long uniform potentiometer wire AB is having a constant potential gradient along its length. The null points for the two primary cells of emfs ε1 and ε2 connected in the manner shown are obtained at a distance of 120 cm and 300 cm from the end A. Find (i) ε1/ ε2 and (ii) position of null point for the cell ε1.

How is the sensitivity of a potentiometer increased?


Would you prefer a voltmeter or a potentiometer to measure the emf of a battery?


The net resistance of an ammeter should be small to ensure that _______________ .


Draw a labelled circuit diagram of a potentiometer to measure the internal resistance ‘r’ of a cell. Write the working formula (derivation is not required). 


Define or describe a Potentiometer.


What are the disadvantages of a potentiometer?


What will be the effect on the position of zero deflection if only the current flowing through the potentiometer wire is increased?


Find the equivalent resistance between the terminals of A and B in the network shown in the figure below given that the resistance of each resistor is 10 ohm.


What will be the effect on the position of zero deflection if only the current flowing through the potentiometer wire is decreased?


When the null point is obtained in the potentiometer, the current is drawn from the ______  


The instrument which can measure terminal potential difference as well as electromotive force (emf) is ______ 


The resistance of the potentiometer wire should ideally be ____________.


In a potentiometer experiment, when the galvanometer shows no deflection, then no current flows through ____________.


The potentiometer is more sensitive, when ______.


Two cells when connected in series are balanced on 8 m on a potentiometer. If the cells are connected with polarities of one of the cell reversed, they balance on 2 m. The ratio of e.m.f's of the two cells is ____________.


A potentiometer wire has length L For given cell of emf E, the balancing length is `"L"/3` from 3 the positive end of the wire. If the length of the potentiometer wire is increased by 50%, then for the same cell, the balance point is obtained at length.


The length of a potentiometer wire is L. A cell of e.m.f E is balanced at length L/3 from the positive end of the wire. If the length of wire increases by L/2, then the same cell will give balance point at length ____________.


If the e.m.f of a cell is not constant in the metre bridge experiment, then the ____________.


Sensitivity of a given potentiometer can be decreased by ______.


A potentiometer wire is 10 m long and has resistance of 2`Omega`/m. It is connected in series with a battery of e.m.f 3 V and a resistance of 10 `Omega`. The potential gradient along the wire in V/m is ______.


In the potentiometer experiment, the balancing length with cell E1 of unknown e.m.f. is ℓ1 cm. By shunting the cell E1 with resistance 'R' which is equal to internal resistance (r) of the cell E1, the balancing length ℓ2 is ______


A wire has a length of 2m and a resistance of 10Ω. It is connected in series with a resistance of 990Ω and a cell of e.m.f. 2V. The potential gradient along the wire will be ______


A potentiometer wire has a length of 4m and resistance of 5Ω. It is connected in series with 495 Ω resistance and a cell of e.m.f. 4V. The potential gradient along the wire is ______


A student connected the circuit as shown in the figure to determine the internal resistance of a cell E1 by potentiometer (E > E1). He is unable to obtain the null point because ______.


In the potentiometer experiment, cells of e.m.f. E1 and E2 are connected in series (E1 > E2). the balancing length is 64 cm of the wire. If the polarity of E2 is reversed, the balancing length becomes 32 cm. The ratio `E_1/E_2` is ______   


It is observed in a potentiometer experiment that no current passes through the galvanometer when the terminals of the cell are connected across a certain length of the potentiometer wire. On shunting the cell by a 2 Ω resistance, the balancing length is reduced to half. The internal resistance of the cell is ______.


The sensitivity of the potentiometer can be increased by ______.


Potentiometer measures potential more accurately because _________.

For measuring voltage of any circuit, potentiometer is preferred to voltmeter because ______.

In a potentiometer of 10 wires, the balance point is obtained on the 7th wire. To shift the balance point to 9th wire, we should ______.


The best instrument for accurate measurement of EMF of a cell is ____________.


A 10 m long wire of uniform cross-section and 20 Ω resistance is used in a potentiometer. The wire is connected in series with a battery of 5 V along with an external resistance of 480 Ω. If an unknown emf E is balanced at 6.0 m length of the wire, then the value of unknown emf is ______.


The instrument among the following which measures the e.m.f of a cell most accurately is ______


In a potentiometer circuit a cell of EMF 1.5 V gives balance point at 36 cm length of wire. If another cell of EMF 2.5 V replaces the first cell, then at what length of the wire, the balance point occurs? 


Consider a simple circuit shown in figure   stands for a variable resistance R′. R′ can vary from R0 to infinity. r is internal resistance of the battery (r << R << R0).

  1. Potential drop across AB is nearly constant as R ′ is varied.
  2. Current through R′ is nearly a constant as R ′ is varied.
  3. Current I depends sensitively on R′.
  4. `I ≥ V/(r + R)` always.

While doing an experiment with potentiometer (Figure) it was found that the deflection is one sided and (i) the deflection decreased while moving from one end A of the wire to the end B; (ii) the deflection increased. while the jockey was moved towards the end B.

  1. Which terminal + or – ve of the cell E1, is connected at X in case (i) and how is E1 related to E?
  2. Which terminal of the cell E1 is connected at X in case (ii)?


Potential difference between the points A and B in the circuit shown is 16 V, then potential difference across 2Ω resistor is ______ V. volt. (VA > VB)


A Daniel cell is balanced on 125 cm lengths of a potentiometer wire. Now the cell is short circuited by a resistance 2 Ω and the balance is obtained at 100 cm. The internal resistance of the Daniel cell is ______.


As a cell age, its internal resistance increases. A voltmeter of resistance 270 Ω connected across an old dry cell reads 1.44 V. However, a potentiometer at the balance point gives a voltage measurement of the cell as 1.5 V. Internal resistance of the cell is ______ Ω.


Two cells of same emf but different internal resistances r1 and r2 are connected in series with a resistance R. The value of resistance R, for which the potential difference across second cell is zero, is ______.


A cell of internal resistance r is connected across an external resistance nr. Then the ratio of the terminal voltage to the emf of the cell is ______.


What should be the diameter of a soap bubble such that the excess pressure inside it is 51.2 Pa? [Surface tension of soap solution = 3.2 × 10−2 N/m]


Draw a neat labelled diagram of Internal resistance of a cell using a potentiometer.


What is the internal resistance of the cell?


The Figure below shows a potentiometer circuit in which the driver cell D has an emf of 6 V and internal resistance of 2 Ω. The potentiometer wire AB is 10 m long and has a resistance of 28 Ω. The series resistance RS is of 2 Ω.

  1. The current Ip flowing in the potentiometer wire AB when the jockey (J) does not touch the wire AB.
  2. emf of the cell X if the balancing length AC is 4.5 m.

Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×