Nuclei with magic no. of proton Z=2, 8,20,28,50,52 and magic no. of neutrons N=2,8,20,28,50,82 and 126 are found to be very stable.
What does the existence of magic number indicate?

Nuclei with magic no. of proton Z=2, 8,20,28,50,52 and magic no. of neutrons N=2,8,20,28,50,82 and 126 are found to be very stable. Verify this by the calculating the proton separation energy S_p for "^120Sn(Z=50) and "^121Sb=(Z=51) . The proton separation energy for a nuclide is the minimum energy required to separate the least rightly bound proton from a nucleus of that nuclide. It is given by S_p=(M_(z-1,N)+M_H-M_(Z,N))c^2 Given "^119ln=118.9058u , "^120Sn=119.902199u , "^121Sb=120.903824u , "^1H=1.0078252u .

Figure shows a potentiometer with a cell of 2.0 V and internal resistance 0.40 Omega maintaining a potential drop across the resistor wire AB. A standard cell which maintains a constant emf of 1.02 V (for very moderate currents upto a few mA) gives a balance point at 67.3 cm length of the wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600 k Omega is put in series with it, which is shorted close to the balance point. The standard cell is then replaced by a cell of unknown emf epsilon and the balance point found similarly, turns out to be at 82.3 cm length of the wire. What purpose does the high resistance of 600 kOmega have? :

A string of mass 2.50 kg is under a tension of 200 N. The length of the stretched string is 20.0 m. If the transverse jerk is struck at one end of the string, how long does the disturbance take to reach the other end?

Assume that each iron atom has a permanent magnetic moment equal to 2 Bohr magneton . The number density of atoms in iron is 8.52 xx 10^28 m^-3 . Find the maximum value of intensity of magnetisation.

Assume that each iron atom has a permanent magnetic moment equal to 2 Bohr magneton . The number density of atoms in iron is 8.52 xx 10^28 m^-3 . Find the maximum value of magnetic induction in an iron bar.

A sample of paramagnetic salt contains 2.0 xx 10^24 atomic dipoles each of dipole moment 1.5 xx 10^-23 JT^-1 . The sample is placed under a homogeneous magnetic field of 0.64 T, and cooled to a temperature of 4.2 K. The degree of magnetic saturation achieved is equal to 15%. What is the total dipole moment of the sample for a magnetic field of 0.98 T and a temperature of 2.8 K? (Assume Curie’s law)

Three cells of emf 2.0 v, 1.8 V and 1.5 V are connected in series. Their internal resistances are 0.05 Omega, 0.7 Omega " and " 1 Omega respectively. If the battery is connected to an external resistor of 4 Omega via a very resistance ammeter, what would be the reading in the ammeter ?

What is the excess pressure inside a bubble of soap solution of radius 5.00 mm,given that the surface tension of soap solution at the temperature (20^@C) is 2.50xx 10 2 N in 1 ? If an air bubble of the same dimension were formed at depth of 40.0 cm inside a container containing the soap solution (of relative density 1.20), what would be the pressure inside the bubble ? (1 atmospheric pressure is 1.01xx 105 Pa).

An item is manufacture by three machines A, B and C. out of the total number of items manufactured during a specified period, 50% are manufactures on A. 30% on B and 20% on C. 2% on the items produced on A and 2% of items produced on B are defective, and 3% of these produced on C are defective. All the items are stored at one godown. One item is drawn at random and is found to be defective. what is the probability that it is manufactured on machine A?