A boy walks towards a stationary plane mirror at a speed of 12ms^1 what is the relative speed of approach of the boy and his image? (a)zero (b)1.2ms^-1 (c) 2.4ms^-1 (d)1.44ms^-1​

The magnitude of the magnetic field at a certain distance from a long, straight conductor is represented by b. what is the magnitude of the magnetic field at twice the distance from the conductor? a. at twice the distance, the magnitude of the field is 4b. b. at twice the distance, the magnitude of the field is 2b. c. at twice the distance, the magnitude of the field is b/2.d. at twice the distance, the magnitude of the field is b/4.e. at twice the distance, the magnitude of the field remains equal to b.