11.

A body is thrown with a velocity of 9.8 m/s making an angle of 30° with the horizontal. It will hit the ground after a time

• 1.5 s

• 1 s

• 3 s

• 2 s

If σ = surface change density, ε = electric permittivity, the dimensions of $\frac{\mathrm{\sigma }}{\mathrm{\epsilon }}$ is same as

• electric force

• electric field intensity

• pressure

• electric charge

Radius of orbit of satellite of earth is R its kinetic energy is proportional to

• $\frac{1}{\mathrm{R}}$

• $\frac{1}{\sqrt{\mathrm{R}}}$

• R

• $\frac{1}{{\mathrm{R}}^3}$

A body executes simple harmonic motion under the action of force F₁ with a time period $\frac{4}{5}$s. If the force is changed to F₂ it executes simple harmonic motion with time period $\frac{3}{5} \mathrm{s}$.If both forces F₁ and F₂ act simultaneously in the same direction on the body, its time period will be

• $\frac{12}{25} \mathrm{s}$

• $\frac{24}{25} \mathrm{s}$

• $\frac{35}{24} \mathrm{s}$

• $\frac{15}{12} \mathrm{s}$

A ballon contains 500 m³ of He at 27°C and 1 atmospheric pressure. The volume of He at − 3°C and 0.5 atmospheric pressure will be

• 700 m³

• 900 m³

• 1000 m³

• 500 m³

A Carnot engine works between temperature 72°C and 27°C. The efficiency of the engine is

• 70 %

• 30 %

• 0 %

• 10 %

A man measure time period of a pendulum (T) in stationary lift. If the lift moves upward with acceleration g /4, then new time period will be

• $\sqrt{\frac{2}{5}} \mathrm{T}$

• $\sqrt{\frac{5}{2}} \mathrm{T}$

• $\frac{\sqrt{5 }\mathrm{T}}{2}$

• $\frac{2 \mathrm{T}}{\sqrt{5}}$

A body of specific heat 0.2 kcal/kg°C is heated through 100°C. The percentage increase in its mass is

• 9 %

• 9.3 x 10^-11 %

• 10 %

• None of these

If E = at + bt², what is the neutral temperature ?

• $- \frac{\mathrm{a}}{2\mathrm{b}}$

• $+ \frac{\mathrm{a}}{2\mathrm{b}}$

• $- \frac{\mathrm{a}}{\mathrm{b}}$

• $+ \frac{\mathrm{a}}{\mathrm{b}}$

Copper has face centred cubic (fcc) lattice with interatomic spacing equals to 2.54 $\stackrel{\circ }{\mathrm{A}}$. The value of lattice constant for this lattice is

• 3.59 $\stackrel{\circ }{\mathrm{A}}$

• 2.54 $\stackrel{\circ }{\mathrm{A}}$

• 1.27 $\stackrel{\circ }{\mathrm{A}}$

• 5.08 $\stackrel{\circ }{\mathrm{A}}$