(vd If is the number of free electrons per unit volume, then total number of electrons in the conductor is n N = n x volume = nAl Total force on the conductor is vd F If represents a current element vector in the direction of current, then vectors and I l l have opposite directions and we can take vdwill l vd= l F B) I [ ] (l F B) The magnitude of the force is F = I l B sin (i) If =0 or 180 , then F = = 0 I l B(0) Thus a current carrying conductor placed parallel to the direction of the magnetic field does not experience any force. (ii) If =90 , then F = sin90o or Fmax = I l B I l B Thus a current carrying conductor placed perpendicular to the direction of a magnetic field experiences a maximum force. 4. Define current sensitivity and voltage sensitivity of a galvanometer. State the factors on which the sensitivity of a moving coil galvanometer depends. Ans. Current sensitivity: It is the deflection produced in the galvanometer when a unitcurrent flows through it. NBA Current sensitivity, Is I k Voltage sensitivity: It is the deflection produced in the galvanometer when a unitpotential difference is applied across its ends. Voltage sensitivity, Vs=α/V =NBA/k RG
(vd If n is the number of free electrons per unit volume, then total number of electrons in the conductor is N = n x volume = nAl Total force on the conductor is F vd If represents a current element vector in the direction of current, then vectors and I l l vdwill have opposite directions and we can take l vd= l F B) [ ] F I (l B) The magnitude of the force is F = I l B sin (i) If =0 or 180 , then F = I l B(0) = 0 Thus a current carrying conductor placed parallel to the direction of the magnetic field does not experience any force. (ii) If =90 , then F = I l B sin90o or Fmax = I l B Thus a current carrying conductor placed perpendicular to the direction of a magnetic field experiences a maximum force. 4. Define current sensitivity and voltage sensitivity of a galvanometer. State the factors on which the sensitivity of a moving coil galvanometer depends. Ans. Current sensitivity: It is the deflection produced in the galvanometer when a unitcurrent flows through it. Current sensitivity, Is NBA I k Voltage sensitivity: It is the deflection produced in the galvanometer when a unitpotential difference is applied across its ends. Voltage sensitivity, Vs=α/V =NBA/k RG
5202-40.docx