11.

In amplitude modulation, sinusoidal carrier frequency used is denoted by ω_c and the signal frequency is denoted by ωm. The bandwidth (Δω_m) of the signal is such that Δω_m << ω_c. Which of the following frequencies is not contained in the modulated wave?

• ωm + ωc

• ωc - ωm

• ωm

• ωm

Cp and Cv are specific heats at constant pressure and constant volume respectively. It is observed that
Cp – Cv = a for hydrogen gas
Cp – Cv = b for nitrogen gas
The correct relationship between a and b is

• a = 14 b

• a = 28 b

• a = 1/14b

• a = 1/14b

A copper ball of mass 100 gm is at a temperature T. It is dropped in a copper calorimeter of mass 100 gm, filled with 170 gm of water at room temperature. Subsequently, the temperature of the system is found to be 75°C. T is given by:(Given : room temperature = 30° C, specific heat of copper = 0.1 cal/gm°C

• 1250°C

• 825°C

• 800°C

• 800°C

A man grows into a giant such that his linear dimensions increase by a factor of 9. Assuming that his density remains same, the stress in the leg will change by a factor of

• 81

• 1/81

• 9

• 9

A magnetic needle of magnetic moment 6.7 × 10^–2 Am² and moment of inertia 7.5 × 10^–6 kg m² is performing simple harmonic oscillations in a magnetic field of 0.01 T.Time taken for 10 complete oscillations is :

• 6.98 s 

• 8.76 s

• 6.65 s

• 6.65 s

An external pressure P is applied on a cube at 0°C so that it is equally compressed from all sides.K is the bulk modulus of the material of the cube and α is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by

• 3α/PK

• 3PKα

• P/3αK

• P/3αK

An observer is moving with half the speed of light towards a stationary microwave source emitting waves at frequency 10 GHz. What is the frequency of the microwave measured by the observer?
(speed of light = 3 × 10⁸ ms^–1)

• 17.3 GHz

• 15.3 GHz

• 10.1 GHz

• 10.1 GHz

Which of the following statements is false?

• A rheostat can be used as a potential divider

• Kirchhoff's second law represents energy conservation

• Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.

• Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.

An electric dipole has a fixed dipole moment , which makes angle θ with respect to the x-axis. When subjected to an electric field , it experiences a torque . When subjected to another electric field  it experiences torque . The angle θ is

• 60°

• 90°

• 30°

• 30°

When a current of 5 mA is passed through a galvanometer having a coil of resistance 15Ω, it shows full-scale deflection. The value of the resistance to be put in series with the galvanometer to convert it into to voltmeter of range 0 – 10 V is

• 2.535 × 10³ Ω

• 4.005 × 10³ Ω

• 1.985 × 10³ Ω

• 1.985 × 10³ Ω