The current density is a solid cylindrical wire of radius $R ,$ as a function of radial distance $r$ is given by $J ( r )= J _{0}\left(1-\frac{ r }{ R }\right) .$ The total current in the radial region $r =0$ to $r =\frac{ R }{4}$ will be
  • A$\frac{5 J _{0} \pi R ^{2}}{32}$
  • B$\frac{5 J _{0} \pi R ^{2}}{96}$
  • C$\frac{3 J _{0} \pi R ^{2}}{64}$
  • D$\frac{ J _{0} \pi R ^{2}}{128}$
AIIMS 2019, Diffcult
art

Download our app
and get started for free

Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*

Similar Questions

  • 1
    The three resistance of equal value are arranged in the different combinations shown below. Arrange them in increasing order of power dissipation.
    View Solution
  • 2
    The circuit shown in the figure consists of a battery of $emf$ $\varepsilon = 10 \,V$ ; a capacitor of capacitance $C = 1.0$ $ \mu F$  and three resistor of values $R_1 = 2$ $\Omega$ , $R_2 = 2$ $\Omega$ and $R_3 = 1$ $\Omega$ . Initially the capacitor is completely uncharged and the switch $S$ is open. The switch $S$ is closed at $t = 0.$
    View Solution
  • 3
    The internal resistance of a $2.1\, V$ cell which gives a current of $0.2\, A$ through a resistance of $10\,\Omega$ is ............. $\Omega$
    View Solution
  • 4
    There are two electric bulbs of $40\, W$ and $100\, W$. Which one will be brighter when first connected in series and then in parallel,
    View Solution
  • 5
    Resistance of a carbon resistor determined from colour codes is $(22000 \pm 5 \%) \Omega$. The colour of third band must be :
    View Solution
  • 6
    Find equivalent resistance $A$ and $B$
    View Solution
  • 7
    Water boils in an electric kettle in $20$ minutes after being switched on. Using the same main supply, the length of the heating element should be. . . . . . .to . . . . . .. times of its initial length if the water is to be boiled in $15$ minutes.
    View Solution
  • 8
    In a hydrogen discharge tube it is observed that through a given cross-section $3.13 \times {10^{15}}$ electrons are moving from right to left and $3.12 \times {10^{15}}$ protons are moving from left to right. What is the electric current in the discharge tube and what is its direction
    View Solution
  • 9
    Two current elements $P$ and $Q$ have current voltage characteristics as shown below :

    Which of the graphs given below represents current voltage characteristics when $P$ and $Q$ are in series.

    View Solution
  • 10
    Of the two bulbs in a house hold circuit, one glows brighter than the other, Which of the two bulbs has a large resistance?
    View Solution