11) To find the position of the null point in a Wheatstone's bridge experiment we use ----
O a microammeter
a galvanometer with zero at the center of the circular scale
a galvanometer with zero of the scale at the extreme left
a suspended type moving coil O galvanometer, where coil is wound on a nonmetallic frame

In a moving coil galvanometer, we use a radial magnetic field so that the galvanometer scale is

The following combination are concerned with experiments of the characterization and use of a moving coil galvanometer. The series combination of variab resistance R, one 100 Omega resistor and moving coil galvanometer is connected to a mobile phone charger having negligible internal resistance. The zero of the galvanometer lies the centre and the pointer can move 30 division full scale on either side depending on the directin of current. The reading of the galvanometer is 10 divisions and the voltages across the galvanometer and 100 Omega resistor are respectively 12mV and 16 mV. The series combination of the galvanometer with a resistnce of R is conneted across an ideal voltage supply of 12 V and this time the galvanometer shows full scale defiention of 30 divisions. The value of R is nearly

During an experiment with a metre bridge, the galvanometer shows a null point when the jockey is pressed at 40.0 cm using a standard resistance of 90 Omega , as shown in the figure. The least count of the scale used in the metre bridge is 1mm. The unknown resistance is

Internal micrometer is a measuring intrument used to measure internal diameter (ID) of a large cylinder bore with high accuracy. Construction is shown in figure. There is one fixed rod B (to the right in figure) and one moved rod A (to the left in figure). It is based on the particle of advancement of a screw when it is rotated in a nut with internal threads. Main scale reading can be directly seen on the hub which is fixed with respect to rod B. When the cap is rotated rod A moves in or cut depending on direction of rotation. The circular scale reading is seen by checking which division of circular scale coincide with the references line This is to be multiplied by LC to get circular scale reading. Least count = value of 1 circular scale division = ("pitch")/("number of division on circular scale") Length of rod A is chosen to match the ID(PQ) to be measured. Zero error is checked by taking reading between standard blocks fixed at normal value of ID to be measured. Zero error is positive if cap end is one the right of the main scale and negative it is on the left side. During zero setting of the above instrument, the end of the cap is on left side of the zero of main scale (i.e. zero of main scale is not visible) and 41^(th) division of circular scale coincides with the reference line, the zero error is -

A nichrome wire AB, 100 cm long and of uniform cross section cross section is mounted on a meter scale the points A and B coinciding with 0 cm and 100 cm marks respectively. The wire has a resistance S = 50 ohm, Ay point C along this wire, between A and B is called a variable point to which on end of and electrical element is commeted. In the following questions this arrangement will be referred to as 'wire AB'. The emf of a battery is determined using the following circuit with 'wire AB'. The galvanometer shows zero delfection when one of its terminals is conneted to point C. If the internal resistance of the battery is 4 ohm, its emf is

In a metre bridge experiment to determine unknown resistance of a coil, how is position of the null point affected if: (i) Galvanometer and cell are interchanged? (ii) Known and unknown resistances are interchanged?

Two identical moving coil galvanometers have 10Omega resistance and full scale deflection at 2muA current. One of them is converted into a voltmeter of 100mA full scale reading and the other into an Ammeter of 1mA full scale current using appropriate resisters. These are then used to measure the voltage and current in the Ohm’s law experiment with R=1000 Omega resistor by using an ideal cell. Which of the following statement(s) is(are) correct?

The instrument used to measure resistance is the Wheatstone bridge with a slide resistance-a wire of high resistivity of length L (Fig. 26.6). Here R is a calibrated resistance, R_x, the unknown resistance. By moving the sliding contact, the current in the galvanometer is made to drop to zero. Making use of this condition (of bridge balance), find the resistance being measured.

Internal micrometer is a measuring intrument used to measure internal diameter (ID) of a large cylinder bore with high accuracy. Construction is shown in figure. There is one fixed rod B (to the right in figure) and one moved rod A (to the left in figure). It is based on the particle of advancement of a screw when it is rotated in a nut with internal threads. Main scale reading can be directly seen on the hub which is fixed with respect to rod B. When the cap is rotated rod A moves in or cut depending on direction of rotation. The circular scale reading is seen by checking which division of circular scale coincide with the references line This is to be multiplied by LC to get circular scale reading. Least count = value of 1 circular scale division = ("pitch")/("number of division on circular scale") Length of rod A is chosen to match the ID(PQ) to be measured. Zero error is checked by taking reading between standard blocks fixed at normal value of ID to be measured. Zero error is positive if cap end is one the right of the main scale and negative it is on the left side. In the above instrument, while measuring an internal diameter. ID is set of 321 mm with no zero error. It cap end is after 7^(th) division adn 17^(th) division of main scale coincides with the reference line, the ID is -

In a conservative force field we can find the radial component of force from the potential energy function by using F = -(dU)/(dr) . Here, a positive force means repulsion and a negative force means attraction. From the given potential energy function U(r ) we can find the equilibrium position where force is zero. We can also find the ionisation energy which is the work done to move the particle from a certain position to infinity. Let us consider a case in which a particle is bound to a certain point at a distance r from the centre of the force. The potential energy of the particle is : U(r )=(A)/(r^(2))-(B)/(r ) where r is the distance from the centre of the force and A andB are positive constants. Answer the following questions. If the total energy of the particle is E=-(3B^(2))/(16A) , and it is known that the motion is radial only then the velocity is zero at