A potentiometer wire of resistance 7r, length 42cm is connected in series with a battery of emf V, internal resistance r and external resistor 2r as shown. At null deflection the balancing length is found to be 5cm. The ratio of the emf of the two cells ę/V will be ?

How to get expertise in Class 10 science this year and get preparation for boardexam

AB is a current carrying conductor in the plane of the paper as shown in the figure below. (i) What is the direction of the magnetic field produced by it at point ‘X’? Write the statement of the rule used to find the direction of field lines. (ii) If the polarity of the battery connected to the wire is reversed, how would the direction of the magnetic field be changed? (iii) Point ‘X’ is at a distance r1 and point ‘Y’ is at a distance r2 (r1

formula of c in curies temperature please ansewr i am waiting for the answer

Describe in operation electro dynamic whattmetermeter

For minimum flux the angle between the magnetic field and normal to the surface is