1
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

A spherical metal ball of density '$$\rho$$' and radius '$$r$$' is immersed in a liquid of density '$$\sigma$$'. When an electric field is applied in the upward direction the metal ball remains just suspended in the liquid. Then the expression for the charge on the metal ball is :

A
$$q=\frac{\left[\frac{4}{3} \pi r^3 \rho g\right]}{\sigma E}$$
B
$$q=\frac{\left[4 \pi r^3(\rho-\sigma) g\right]}{3 E}$$
C
$$q=\frac{\left[4 \pi r^2 \rho g\right]}{\sigma E}$$
D
$$q=\frac{\left[4 \pi r^2(\rho-\sigma) g\right]}{E}$$
2
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

In an adiabatic expansion of air, the volume is increased by $$6.2 \%$$. The percentage change in pressure is $$(\gamma=1.4)$$

A
8.68
B
4.84
C
6.48
D
2.24
3
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Water from a tap of cross-sectional area $$1 \mathrm{~cm}^2$$, falls vertically downwards at $$2 \mathrm{~m} / \mathrm{s}$$. The cross sectional area of the stream, $$20 \mathrm{~cm}$$ below the tap is (assume that pressure is constant throughout and the flow is streamlined; $$\left(\mathrm{g}=10 \mathrm{~ms}^{-2}\right)$$

A
7.07 cm$$^2$$
B
1 cm$$^2$$
C
0.707 cm$$^2$$
D
2 cm$$^2$$
4
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

COMEDK 2023 Evening Shift Physics - Capacitor Question 5 English

In the figure, first the capacitors are fully charged by closing the key $$\mathrm{K}$$. Then after opening the Key a dielectric material with dielectric constant 2 is filled in the space between the plates of both the capacitor. At this state the ratio of the Charge on the capacitor $$C_1$$ to that of $$C_2$$ is:

A
1 : 1
B
3 : 2
C
2 : 1
D
1 : 2
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