What is the maximum uncertainty in the measurementof the oscillation frequency in a Josephson junctionif the voltage standard of 1 mV is to be maintainedwithin 1 part in 1010? Assume a referencefrequency of 483.6 GHz.

Physics 2 for Engineering Week 4 Notes 26 September – 29 September Chapter 23 Electric potential energy is a scalar quantity Unit is Joules (J) Potential energy for two point charges assuming U = 0 waen r = infinaty U = kQq / r Review: F = kQq / r 2 E = kq / r 2 Electric potential is a scalar quantity Unit of electric potential is volts (V) 1 V = 1 J / C Unit of electric field is N / C or V / m Assume V = 0 when r = inainity V = kq / r ΔV = E * d at constant electric field For collection of point charges V = Σ kQ / r E direction points from positive charge to negative charge Positive charge moves in the direction of E from high to low potential Negative charge moves opposite to the direction of E from low to high potential E is perpendicular to equipotential lines For infinitely long cylinder or wire V b– V a λ / 2πƐ * l0 (r /r )b a For ring of charge V = Q / 4πƐ √(x0+a )2 2 Point charge equipotential lines are spherical Infinite line equipotential lines are cylindrical Infinite sheet equipotential lines are flat surfaces V = U / q U = qV