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