Q- Kr-85 is a radioactive isotope that is used in measuring paper thickness. It decays by emission with a half-life of 10.8 years
(a) Write down the decay equation showing the daughter isotope and decay products of this process.
(b) A Kr-85 source had activity 30 mCi when new. Estimate its activit…
Q- Consider an object of mass m, moving in a circular orbit, subject to a central attractive for F whose magnitude is given by F(r) = h/r3.
(a)What are the dimensions of h?
(b) Show that the angular momentum for the motion is uniquely determined by h and m.
(c) What is the resulting relatio…
Q- In an experiment with cosmic rays, a vertical beam of particle that have charge of magnitude 3e and mass 12 times the proton mass enters a uniform horizontal magnetic field of 0.250 T and is bent in a semicircle of diameter 95.0 cm as shown in the diagram
(a) Find the speed of the particles an…
Q- The diagram shows the end of a fiber optic cable with core refractive index 1.5 and cladding refractive index 1.4
(a) Find the critical angle at which light in the core is just totally internally reflected at X.
(b) Find the angle of incidence at A for light which is just internally reflecte…
Q- Figure shows the standing wave on a string, oscillating at frequency fo.
(a) How many antinodes will there be if the frequency is doubled to 2fo.
(b) If the tension in the string is increased by a factor of four, for what frequency will the string continue to oscillate as a standing wave with…
Q- A rocket is fired at an angle of 600 with horizontal and accelerates in a straight line at 25ms-2 for 2.5s before the rocket motor stops and it eventually falls to the ground. Neglecting air resistance
(a) Make a labelled sketch of the rockets trajectory starting from the launch point. Include …
Q- Two masses 5 kg and 15 kg are moving along x direction with velocities of 10 m/s and 2 m/s respectively. At an instant they are at positions 10 m and 70 m respectively
(A) Find position of their center of mass at this instant.
(B) If the two will collide inelastically what is their common velo…
(On request: Fiaza Ali)
Q- A spherical brass shell of mass 2.50 kg barely floats in water such that it is completely submerged with the waterline just at its top. The inside of the shell is completely evacuated. The density of brass is 8600 kg/m3 and that of water is 1000 kg/m3.
(a) calculate the …
Q- A mass in the form of a solid cylinder, of radius R acted upon by no forces, moves parallel to its axis through a uniform cloud of fine dust, of volume density ρ, which is at rest. If the particles of dust which meet the mass adhere to it, and if M and u be the mass and the velocity at the begi…
Q- Block A of mass m = 10 kg is pulled from rest, on a horizontal surface by a massless rope passing over a pulley of same mass m = 10 kg, radius R = 0.25 m and moment of inertia I = 1.2 kg m2, rotates freely about its axis. The force applied at the end of the rope is P = 750 N. If the coefficient…
Q- Find the current necessary to stablish a flux of ø = 3*10-4 Wb in the series magnetic circuit (shown in figure) consist of two parts of cast iron and steel cores. Length of each core is l = 0.3 m and the area of cross-section is A = 5*10-4 m2. Relative permittivity of cast iron is 5000 and that …
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