**Q1.** Where on the surface of Earth is the vertical component of Earthâ€™s magnetic field zero? Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â

**Q2.** The horizontal component of the earthâ€™s magnetic field at a place is *B *and angle of dip is 60Â°. What is the value of vertical component of earthâ€™s magnetic field at equator?

**Q3.** A magnetic needle, free to rotate in a vertical plane, orients itself vertically at a certain place on the Earth. What are the values of (i) horizontal component of Earthâ€™s magnetic field and (ii) angle of dip at this place? Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â

**Q4.** Where on the surface of Earth is the angle of dip 90^{0}? Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â

**Q5.** If the horizontal and vertical components of the Earthâ€™s magnetic field are equal at a certain place, what would be the angle of dip at that place? Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â

**Q6. **Â Â Â Â A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip down at 60Â° with the horizontal. The horizontal component of the earthâ€™s magnetic field at the place, is known to be 0.4 G. Determine the magnitude of the earthâ€™s magnetic field at the place. Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â

**Q7.** (i) Name the three elements of the Earthâ€™s magnetic field.

(ii) Where on the surface of the Earth is the vertical component of the Earthâ€™s magnetic field zero?Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â

**Q8.** The horizontal component, of the earthâ€™s magnetic field, at a place is Â 1/âˆš3 Â times its vertical component there. Find the value of the angle of dip at that place. What is the ratio of the horizontal component to the total magnetic field of the earth at that place? Â Â **Â **

**Q9.** A compass needle, free to turn in a vertical plane orients itself with its axis vertical at a certain place on the earth. Find out the values of (i) horizontal component of earthâ€™s magnetic field and (ii) angle of dip at the place. Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â

**Q10.** The apparent dip at two planes, perpendicular to each other are *Î´*1 and *Î´*2 respectively, if *Î´* be the real dip, prove that .

**ANSWERS**