12 13 14 For question numbers 11 12 13 and 14 two statements are given one labelled Assertion A and the other labelled Reason R Select the correct answer to these questions from the codes a b c and d as given below a Both A and R are true and R is the correct explanation of A b Both A and R are true but R is NOT the correct explanation of A c A is true but R is false d A is false and R is also false Assertion A To convert a galvanometer in to ammeter a small resistance shunt is connected in parallel to the coil of galvanometer Reason R An ideal ammeter has infinite resistance Assertion A The wire of potentiometer is made by constantan and manganin Reason R Constantan and manganin are alloys and dependence of resistivity of alloys in temperature is negligible Assertion A A particle will follow helical path in magnetic field if its velocity v and direction of magnetic field B are at angle of Reason R The component vsin o will provide the centripetal force and magnetic field will not apply any force on the component vcos p Assertion A In a metallic wire if we increase the temperature of wire the resistance of the wire also increases Reason R on increasing the temperature thermal velocity of electrons decreases and dingropoor in this way number of collision decreases 1 1 1