Physics Test 107

In a common emitter transistor amplifier, an input signal of 10 mV is applied. Due to this signal, the change in base current is 50 µA and the corresponding change in collector current is 5 mA. If the load resistance in the collector emitter circuit is 5 kΩ, the change in output voltage will be 

A long, cylindrical iron core of cross-sectional area 5.00 cm² is inserted into a long solenoid having 2000 turns m^–1 and carrying a current 2.00A. The magnetic field inside the core is found to be 1.57 T. Neglecting the end effects. The magnetization M is :- 

A particle is projected from ground at an angle such that it covers maximum horizontal distance on ground. In this case the angle between initial and final velocity vector is :-

During free expansion of an ideal gas under adiabatic condition, the internal energy of the gas 

2kg of ice at –20°C is mixed with 5kg of water at 20°C. The water content of final mixture is (Latent heat of ice = 80 kcal/kg, specific heat of water = 1kcal kg^–1 °C^–1, specific heat of  ice = 0.5 kcal kg^–1°C^–1)

In a reference frame K, two particles move along the X-axis, one of mass m₁ with velocity  and the other of mass m₂ with velocity . There exists another reference frame K₀  in which the total kinetic energy of the two masses m₁ and m₂ will be the minimum. The instantaneous velocity  of the reference frame K₀ in the reference frame K will be 

A spring supports a mass of 5g which perform damped oscillations. It is found to have successive maxima of 2.1 cm and 1.3cm. If the damping coefficient b is 10 g s^–1 , find the stiffness of the spring. [given  im (2.1/1.3 = 0.479)] 

Spring of spring constant 1200 Nm^–1 is mounted on a smooth frictionless surface and attached to a block of mass 3 kg. Block is pulled 2 cm to the right and released. The time taken by block to cover a distance of 1cm after release is 

Two planets P₁ and P₂ having masses M₁ and M₂ revolve around the Sun in elliptical orbits, with time periods T₁ and T₂, respectively. The minimum and maximum distances of planet P₁ from the Sun are R and 3R, respectively, whereas for planet P₂ these are 2R and 4R, respectively, where R is a constant. Assuming M₁ and M₂ are much smaller than the mass of the Sun, the magnitude of T₂/T₁ is 

In a parallel plate capacitor the distance between the plates is 10 cm. Two dielectric slabs of thickness 5 cm each and dielectric constant K₁ = 2 and K₂ = 4 respectively, are inserted between the plates.  A potential of 100 V is applied across the capacitor as shown in the figure. The value of the net bound surface charge density at the interface of the two dielectrics is