Take Pure

20.    What force must be applied to a steel wire 6 m long and diameter 1.6 mm to produce an extension of 1 mm? (Y for steel = 2X10 11 N/m 2 ).

19.    Two slits in Young’s double slit experiment are 0.18 mm apart and fringes are observed on a screen 80 cm away. If the fourth bridge fringe is situated at a distance of 10.8 mm from center fringe, find the wavelength of light.

18.    At what temperature will be velocity of sound is double its value at 273 K?

15.    What is the impedance of a series combination of a resistance 1000 Ω and a capacitance of 2 µF at a frequency of 50 Hz?

14.    An electric lamp is rated as 220 V – 100 W. What is its electric resistance? What power does it consume if it used a circuit of 110 V?

13. Two small spheres of charge +10 µC and +40 µC are placed 6 cm apart. Find location of point between them where the field strength is zero.