Potentiometer

In a potentiometer arrangement, a cell of emf 1.2V gives a balance point at 30cm length of the wire. This cell is now replaced by another cell of unknown emf. If the ratio of emfs of the two cells is 1.5, Calculate the difference in the balancing length of the potentiometer wire in the two cases

• 5cm

• 10cm

• 15cm

• 20cm

Four resistances of 16 ohm, 12 ohm. 4 ohm & 9 ohm respectively are connected in cyclic order to form a wheatstone bridge. Calculate the resistance to be connected in parallel with 9 ohm resistance to balance the bridge.

• 3ohm

• 12ohm

• 13 ohm

• 18 ohm

A potentiometer having wire 10m long is connected to a battery having a steady voltage. A lechlanche cell gives a null point at 750cm. If the length of potentiometer wire is increased by 100cm, find the new position of null point.

• 625cm

• 725cm

• 825cm

• 925cm

A 4m long wire of resistance 8 ohm is connected in series with a battery of emf 2V and a resistor of 7 ohm. The internal resistance of the battery is 1 ohm. What is the potential gradient along the wire?

• 1.00 V/m

• 0.75 V/m

• 0.50 V/m

• 0.25 V/m

The length of potentiometer wire is L. A cell of emf is balanced at the length of L/3 from the positive end of the wire. If the length of the wire is increased by L/2, at what distance will the same cell give a balance point.

• L/2

• L/3

• L/4

• L/5

A potentiometer wire of length 1m has a resistance 15ohm. It is connected to a 5V source with a resistance of 5ohm. Determine the emf of the primary cell which has a balance point at 60cm.

• 2.5 V

• 2V

• 2.25V

• 4.5V

A cell can be balanced against 110cm and 100cm of potentiometer wire respectively when in open circuit and when short circuited through a resistance of 10 ohm. Find the internal resistance of the cell.

• 0.5 ohm

• 0.1 ohm

• 1 ohm

• 2 ohm

The sestivity of a potentiometer is increased by

• increasing the emf of the cell

• increasing the length of the potentiometer wire

• decreasing the length of potentiometer wire

• none of the above

A potential gradient is created in the wire by a standard cell for the comparison of emfs of two cells in a potentiometer experiment. Which possibility of the following will cause failure of the experiment.

• the emf of standard cell is higher than that of the other cells

• the diameter of the wires is equal and similar

• the number of wires is ten

• the emf of the standard cell is less than those of both the cells

Balance point is D when only S is in gap2. If S' is connected in parallel to s, then the balance point shifts

• Left of D

• Right of D

• Remains at D

• Left if S' is less thanS and Right if S' is greater than S

Tags

NGSS.HS-PS2-1