AOD + Electricity no. 2

Question no. 1

A constant voltage is applied between the two ends of a unifrom metallic wire. Some heat is developed in it, the heat developed is doubled if
the radius of the wire is doubled
  the length of the wire is doubled
  both the length and radius of the wire are halved
  both the length and radius of the wire doubled.

Question no. 2

Fuse wire should have
  low resistance , low melting point
  low resistance , low melting point
  high resistance , low melting point
high resistance , high melting point

Question no. 3

An electric kettle has two heating elements . One brings it to the boil in 10 minutes and the other in 15 minutes. if two heating filaments are connected in parallel , the water in kettle will boil in
6 min
  8 min
  25 min
  5 min

Question no. 4

An electric bulb is rated 220 V and 100 watt. Power consumed by it when operated on 110 volt is
25 watt
  50 watt
  75 watt
  90 watt

Question no. 5

If the electric current in a lamp decreases by 5% , then the power output decreases by
  2.5 %
  5%
  10%
  20%

Question no. 6

In a potentiometer experiment , the balancing with a cell is at length 240cm. On shunting the cell with a resistance of 2 ohm . the balancing length becomes 120 cm. the internal resistance pf the cell is
  2 ohm
  4 ohm
  0.5 ohm
  1 ohm

Question no. 7

Dimensions of resistance in an elcetric circuit , in terms of dimensions of mass M , of length L , of time T and of current I , would be
M L² T^-2
M L² T^-1 I^-1
  M L² T^-3 I^-2
  M L² T^-3 I^-1

Question no. 8

Current provided by a battery is maximum when
  internal resistance is equal to external resistance
  internal resistance is greater than external resistance
  internal resistance is less than external resistance
  none of these

Question no. 9

When a body is earth connected , electrons from the earth flow into the body. This means the body is
Charged negatively
  an insulator
uncharged
  charged positively

Question no. 10

A wire has a resistance of 10 ohm . it is stretched by one-tenth of its original length. then its resistance will be
9 ohm
10 ohm
  11 ohm
  12.1 ohm

Question no. 11

A wire of resistance R is cut into n equal parts. These parts are then connected in parallel. The equivalent resistance of the combination will be
  n R
  R/n
  n/R
R / n²

Question no. 12

The distance moved by the particle in time x = t³ - 12² + 6t + 8 . at the instant when its acceleration is zero . , the velocity is
  42
  -42
  48
  -48

Question no. 13

In a sphere the rate of change of surface area is
  8 π times the rate of change of diameter
  2π times the rate of change of diameter
  2π times the rate of change of radius
  8 π times the rate of change of radius

Question no. 14

for the function f(x) = x + 1/x , x ∈ [1,3] , the value of c for the Langrange's mean value theroem is
1
√3
2
none of these

Question no. 15

The equation to the normal to the curve y = sinx at (0 , 0) is
  x = 0
  y = 0
  x + y = 0
  x - y = 0

Question no. 16

The curves y = ae^x and y = be^-x cut orthogonally , if
a = b
  a = -b
  ab = 1
  ab = 2

Question no. 17

The function f(x) = -x/2 + sinx defined on [-π/3 , π/3 ] is
  increasing
  decreasing
  constant
  none of these

Question no. 18

If the function f(x) = x² - kx + 5 is inceasing on [2 , 4] , then
  k ∈ (2, ∞)
  k ∈ ( -∞,2)
  k ∈ (4, ∞)
  k ∈ ( -∞ , 4)

Question no. 19

A cylinder is inscribed in a sphere of radius r. What is the height of the cylinder of maximum volume ?
  2r/√3
  r/√3
  2r
  r√3

Question no. 20

What is the maximum value of the function f(x) = 4sin²x + 1 ?
  5
  3
  2
  1