Class 12th

A 750 Hz, 20 V (rms) source is connected to a resistance of 100Ω, an inductance of 0.1803H and a capacitance of 10µF all in series. The time in which the resistance (heat capacity 2 J/°C) will get heated by 10°C. (assume no loss of heat to the surroundings) is close to:

In the circuit shown in the figure, the total charge is 750 µC and the voltage across capacitor C? is 20 V. Then the charge on capacitor C? is

In a Young's double slit experiment, light of 500 nm is used to produce an interference pattern. When the distance between the slits is 0.05 mm, the angular width (in degree) of the fringes formed on the distance screen is close to:

A charged particle carrying charge 1µC is moving with velocity (2î + 3ĵ + 4k) ms⁻¹. If an external magnetic field of (5î + 3ĵ – 6k) * 10⁻³T exists in the region where the particle is moving then the force on the particle is F⃗ * 10⁻⁹ N. The vector F⃗ is:

In a radioactive material, fraction of active material remaining after time t is 9/16. The fraction that was remaining after t/2 is

Model a torch battery of length l to be made up of a thin cylindrical bar of radius 'a' and a concentric thin cylindrical shell of radius 'b' filled in between with an electrolyte of resistivity ρ (see figure). If the battery is connected to a resistance of value R, the maximum joule heating in R will take place for:

An elliptical loop having resistance R, of semi major axis a and semi minor axis b is placed in a magnetic field as shown in the figure. If the loop is rotated about the x-axis with angular frequency ω, the average power loss in the loop due to joule heating is:

When the wavelength of radiation falling on a metal is changed from 500 nm to 200 nm the maximum kinetic energy of the photoelectrons becomes three times larger. The work function of the metal is close to:

A uniform thin rope of length 12 m and mass 6 kg hangs vertically from a rigid support and a block of mass 2 kg is attached to its free end. A transverse short wave-train of wavelength 6 cm is produced at the lower end of the rope. What is the wavelength of the wave train (in cm) when it reaches the top of the rope?

The equation of the normal to the curve y = (1+x)²? + cos²(sin?¹x) at x=0 is