If the lattice parameter for a crystalline structure is 3.6 A, then atomic radius in fcc crystal is

• 1.18 A

• 2.10 A

• 2.92 A

• 2.92 A

If the error in the measurement of radius of sphere is 2%, then the error in the determination of volume of the sphere will be

• 4%

• 6%

• 8%

• 8%

3.

A roller coaster is designed such that riders experience " weightlessness" as they go round the top of a hill whose radius of curvature is 20 m.  The speed of the car at the top of the hill is between

• 14 m/s and 15 m/s

• 15m/s and 16 m/s

• 16 m/s and 17 m/s

• 16 m/s and 17 m/s

The ratio of the radii of gyration of a circular disc to that of a circular ring, each of same mass and radius, around their respective axes is 

Water falls from a height of 60 m at the rate of 15 kg /s to operate a turbine. The losses due to frictional 

• 8.1 kW

• 10.2 kW

• 12.3 kW

• 12.3 kW

The distance travelled by a particle starting from rest and moving with an acceleration 4/3 ms^-2 in the third second is

• 6 m

• 4 m

• 10/3

• 10/3

A particle shows distance -time curve as given in this figure. The maximum instantaneous velocity of the particle is around the point

• B

• C

• D

• D

A closed loop PQRS carrying a current is placed in a uniform magnetic field. If the magnetic forces on segments PS, SR and RQ are F₁, F₂ and F₃ respectively and are in the plane of the paper and along the directions shown, the force on the segment of QP is

• F₃ - F₁-F₂

• 
• 
• 

Three forces acting on a body are shown in the figure. To have the resultant force only along the y-direction, the magnitude of the minimum additional force needed is

• 0.5 N

• 1.5 N

• 
• 

A shell of mass 200 g is ejected from a gun of mass 4 g by an explosion that generates 1.05 kJ of energy. The initial velocity of the shell is

• 100 ms^-1

• 80 ms^-1

• 40 ms^-1

• 40 ms^-1