YASH CLASSES
9. ELECTRIC CURRENT
77. A
wire has
a resistance of 10 Ω .
metal
into
wire of length
half to original .
calculate the
resistance of the
new wire .
What
percentage change in its resistance ?
78. A wire has a resistance
of 20 Ω . metal
into
wire of length twice
to original .
calculate the
resistance of the
new wire .
What
percentage change in its resistance ?
79. A wire
has a resistance of 30
Ω . metal
into
wire of length double to original .
calculate the
resistance of the
new wire .
What
percentage change in its resistance ?
80. A wire has a resistance
of 28 Ω . metal
into
wire of length
¼ to original .
calculate the
resistance of the
new wire .
What
percentage change in its resistance ?
81. A metal
wire of specific resistance
29 x 10-8Ωm and
length 2.58 m has
a resistance
4 Ω . finds its
radius .
82. A
metal wire of
specific resistance
30 x 10-8Ωm and
length 3.8 m has
a
resistance 7 Ω .
finds its radius .
83. A
metal wire of
specific resistance
28 x 10-8Ωm and
length 1.98 m has
a
resistance 7 Ω .
finds its radius .
84. A
metal wire of
specific resistance
50 x 10-8Ωm and
length 5.8
m has
a
resistance 10 Ω .
finds its radius .