142783 A frame made of metallic wire enclosing a surface area $A$ is covered with a soap film. If the area of the frame of metallic wire is reduced by $50 \%$, the energy of the soap film will be changed by

142784 A small coin is resting on the bottom of a beaker filed with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure).

How fast is the light travelling in the liquid?

142785 Two tubes of same length and diameters $4 \mathrm{~mm}$ and $8 \mathrm{~mm}$ are joined together to form a $U$ shaped tube open at both the ends. If the $U$ tube contains water, then the difference between the levels of water in the two limbs of the tube is
(Surface tension of water at the temperature of experiments is $7.3 \times 10^{-2} \mathrm{Nm}^{-1}$, angle of contact $=0^{0}$, density of water $=1.0 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}$ and acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

142786 A long cylindrical glass vessel has a pinhole of diameter $0.2 \mathrm{~mm}$ at its bottom. The depth in which the vessel can be lowered vertically in deep water bath without the water entering into the vessel is
(Surface tension of water, $T=\mathbf{T}=\mathbf{0 . 0 7}$ $\mathrm{Nm}^{-1}$ acceleration due to gravity, $g=10 \mathrm{~ms}^{-2}$ )

142783 A frame made of metallic wire enclosing a surface area $A$ is covered with a soap film. If the area of the frame of metallic wire is reduced by $50 \%$, the energy of the soap film will be changed by

142784 A small coin is resting on the bottom of a beaker filed with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure).

How fast is the light travelling in the liquid?

142785 Two tubes of same length and diameters $4 \mathrm{~mm}$ and $8 \mathrm{~mm}$ are joined together to form a $U$ shaped tube open at both the ends. If the $U$ tube contains water, then the difference between the levels of water in the two limbs of the tube is
(Surface tension of water at the temperature of experiments is $7.3 \times 10^{-2} \mathrm{Nm}^{-1}$, angle of contact $=0^{0}$, density of water $=1.0 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}$ and acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

142786 A long cylindrical glass vessel has a pinhole of diameter $0.2 \mathrm{~mm}$ at its bottom. The depth in which the vessel can be lowered vertically in deep water bath without the water entering into the vessel is
(Surface tension of water, $T=\mathbf{T}=\mathbf{0 . 0 7}$ $\mathrm{Nm}^{-1}$ acceleration due to gravity, $g=10 \mathrm{~ms}^{-2}$ )

142783 A frame made of metallic wire enclosing a surface area $A$ is covered with a soap film. If the area of the frame of metallic wire is reduced by $50 \%$, the energy of the soap film will be changed by

142784 A small coin is resting on the bottom of a beaker filed with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure).

How fast is the light travelling in the liquid?

142785 Two tubes of same length and diameters $4 \mathrm{~mm}$ and $8 \mathrm{~mm}$ are joined together to form a $U$ shaped tube open at both the ends. If the $U$ tube contains water, then the difference between the levels of water in the two limbs of the tube is
(Surface tension of water at the temperature of experiments is $7.3 \times 10^{-2} \mathrm{Nm}^{-1}$, angle of contact $=0^{0}$, density of water $=1.0 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}$ and acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

142786 A long cylindrical glass vessel has a pinhole of diameter $0.2 \mathrm{~mm}$ at its bottom. The depth in which the vessel can be lowered vertically in deep water bath without the water entering into the vessel is
(Surface tension of water, $T=\mathbf{T}=\mathbf{0 . 0 7}$ $\mathrm{Nm}^{-1}$ acceleration due to gravity, $g=10 \mathrm{~ms}^{-2}$ )

142783 A frame made of metallic wire enclosing a surface area $A$ is covered with a soap film. If the area of the frame of metallic wire is reduced by $50 \%$, the energy of the soap film will be changed by

142784 A small coin is resting on the bottom of a beaker filed with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure).

How fast is the light travelling in the liquid?

142785 Two tubes of same length and diameters $4 \mathrm{~mm}$ and $8 \mathrm{~mm}$ are joined together to form a $U$ shaped tube open at both the ends. If the $U$ tube contains water, then the difference between the levels of water in the two limbs of the tube is
(Surface tension of water at the temperature of experiments is $7.3 \times 10^{-2} \mathrm{Nm}^{-1}$, angle of contact $=0^{0}$, density of water $=1.0 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}$ and acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

142786 A long cylindrical glass vessel has a pinhole of diameter $0.2 \mathrm{~mm}$ at its bottom. The depth in which the vessel can be lowered vertically in deep water bath without the water entering into the vessel is
(Surface tension of water, $T=\mathbf{T}=\mathbf{0 . 0 7}$ $\mathrm{Nm}^{-1}$ acceleration due to gravity, $g=10 \mathrm{~ms}^{-2}$ )