what is emf physics

c rom equation 6.22 (a) it is clear that (!. a ^ , and we can easily compare the emf's of two cells with a potentiometer. First, the primary circuit is completed by connecting the positive pole of the battery of emf s to the terminal A and the negative pole to t..

I - -, where A R is the resistance of the electrolyte. In the case of a copper voltameter with copper electrode, this back e.m.f. is insignificant, as shown in [Fig. 9.14 (a)]. This is because the S0 4 ~~ ion moves towards the copper anode and forms CuS0 4 , which go..

Consider a closed conducting loop ABCD, with the arm CD sliding, placed in a horizontal plane. Let B be a uniform magnetic field perpendicular to the plane of the loop and directed into it. Let the conductor CD be moved towards right with a velocity v as shown in Fig. 15.7..

The experimental arrangement for the study of variation of thermo e.m.f. with temperature is as shown in [Fig. 9.3 (a)]. A suitable thermocouple (say Copper-Iron) is selected. One junction is immersed in an oil, so that it can be raised to high temperature on heating.. The..

Thermo e.m.f. of a thermocouple is measured using a potentiometer. The first step is to make the potentiometer to read potential difference of the order of a few microvolt. This is called calibration or standardisation of potentiometer. Let us consider a numerical problem. Exa..

. Due-to this positive charge of the ions opens up and hence a resultant positive charge is obtained at end Q. Thus end P of the rod becomes negative and end Q becomes positive and hence the rod behaves as a battery of emf Bv..

Consider a coil of N turns placed in a uniform magnetic field B such that the normal to the coil makes an angle 0 with the direction of B. The flux linked wit..

The direction of the induced e.m.f is given by the Russian Scientist Lenz. The direction of the induced e.m.f is such that it opposes the cause producing the change of flux. Induced e.mif. E - - ^ . The negative sign is put to show that the current due to the indu..

The armature coil in a motor rotates in a magnetic field. So an e.m.f. is induced in it due to the change of flux. By Lenz's law this e.m.f. opposes the applied e.m.f. E and hence called back e.m.f denoted by E b . The equivalent circuit of a motor is as shown i..