1
JEE Main 2014 (Offline)
+4
-1
A parallel plate capacitor is made of two circular plates separated by a distance $$5$$ $$mm$$ and with a dielectric of dielectric constant $$2.2$$ between them. When the electric field in the dielectric is $$3 \times {10^4}\,V/m$$ the charge density of the positive plate will be close to:
A
$$6 \times {10^{ - 7}}\,\,C/{m^2}$$
B
$$3 \times {10^{ - 7}}\,\,C/{m^2}$$
C
$$3 \times {10^4}\,\,C/{m^2}$$
D
$$6 \times {10^4}\,\,C/{m^2}$$
2
JEE Main 2013 (Offline)
+4
-1
Two capacitors $${C_1}$$ and $${C_2}$$ are charged to $$120$$ $$V$$ and $$200$$ $$V$$ respectively. It is found that connecting them together the potential on each one can be made zero. Then
A
$$5{C_1} = 3{C_2}$$
B
$$3{C_1} = 5{C_2}$$
C
$$3{C_1} + 5{C_2} = 0$$
D
$$9{C_1} = 4{C_2}$$
3
AIEEE 2012
+4
-1
The figure shows an experimental plot for discharging of a capacitor in an R-C circuit. The time constant $$\tau$$ of this circuit lies between
A
100 sec and 150 sec
B
0 and 50 sec
C
50 sec and 100 sec
D
150 sec and 200 sec
4
AIEEE 2010
+4
-1
Let $$C$$ be the capacitance of a capacitor discharging through a resistor $$R.$$ Suppose $${t_1}$$ is the time taken for the energy stored in the capacitor to reduce to half its initial value and $${t_2}$$ is the time taken for the charge to reduce to one-fourth its initial value. Then the ratio $${t_1}/{t_2}$$ will be
A
$$1$$
B
$${1 \over 2}$$
C
$${1 \over 4}$$
D
$$2$$
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