1
WB JEE 2022
+1
-0.25

A battery of emf E and internal resistance r is connected with an external resistance R as shown in the figure. The battery will act as a constant voltage source if

A
r << R
B
r >> R
C
r = R
D
It will never act as a constant voltage source.
2
WB JEE 2022
+2
-0.5

Find the equivalent capacitance between A and B of the following arrangement :

A
C
B
3C
C
$${{2C} \over 3}$$
D
$${{3C} \over 2}$$
3
WB JEE 2022
+2
-0.5

Three concentric metallic shells A, B and C of radii a, b and c (a < b < c) have surface charge densities +$$\sigma$$, $$-$$$$\sigma$$ and +$$\sigma$$ respectively. The potential of shell B is

A
$$(a + b + c){\sigma \over {{\varepsilon _0}}}$$
B
$${{\sigma c} \over {{\varepsilon _0}}}$$
C
$$\left( {{{{a^2}} \over c} - {{{b^2}} \over c} + c} \right){\sigma \over {{\varepsilon _0}}}$$
D
$$\left( {{{{a^2}} \over c} - b + c} \right){\sigma \over {{\varepsilon _0}}}$$
4
WB JEE 2021
+1
-0.25

The carbon resistor with colour code is shown in the figure. There is no fourth band in the resistor. The value of the resistance is
A
24 M$$\Omega$$ $$\pm$$ 20%
B
14 k$$\Omega$$ $$\pm$$ 5%
C
24 k$$\Omega$$ $$\pm$$ 20%
D
34 k$$\Omega$$ $$\pm$$ 10%
EXAM MAP
Medical
NEET