11.

A body under the action of a force, acquires an acceleration of 1 ms^-2. The mass of this body must be

• 

• 20 kg

• 10 kg

• 10 kg

A bar magnet having a magnetic moment of 2 x 10⁴ JT^-1 is free to rotate in a horizontal plane. A horizontal magnetic field B = 6 x 10^-4 T exists in the space. The work  is done in taking the magnet slowly from a direction parallel to the field to a direction 60^o from the field is

• 0.6 J

• 12 J

• 6 J

• 6 J

If  is the force acting on a particle having position vector  be the the torque of this force about the origin, then

A wave in a string has an amplitude of 2 cm. The wave travels in the +ve direction of x -axis with a speed of 128 ms^-1 and it is noted that 5 complete waves fit in 4 m length of the string. The equation describing the wave is

• y = (0.02) m sin (7.85 x +1005t)

• y = (0.02) m sin (15.7 x -2010t)

• y = (0.02) m sin (15.7 x + 2010t)

• y = (0.02) m sin (15.7 x + 2010t)

A simple pendulum performs simple harmonic motion about x = 0 with an amplitude a and time period T. the speed of the pendulum at x = a/2 will be

• 

• πa / T

• 3π²a / T

• 3π²a / T

A block body t 227^o C radiates heat at the rate of 7 cal cm^-2 s^-1. At  a temperature of 727^o C, the rate of heat radiated in the same units will be 

• 60

• 50

• 112

• 112

The internal energy change in a system that has absorbed 2 Kcal of heat and done 500 J of work is 

• 8900 J

• 6400 J

• 5400 J

• 5400 J

An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water jet. What is the rate at which kinetic energy is imparted to water?

• mv³ /2

• mv³

• mv²/2

• mv²/2

Which one of the following equations of motion represents simple harmonic motion? 

• Acceleration = -k_o x +k₁x²

• Acceleration =-k(x+a)

• Acceleration = k (x+a)

• Acceleration = k (x+a)

In a thermodynamic process which of the following statements is not true?

• In an adiabatic process, the system is insulated from the surroundings

• In an isochoric process pressure remains constant

• In an isothermal process, the temperature remains constant

• In an isothermal process, the temperature remains constant