Invariance: A journal with a difference
The equation v = a*del_t is sometimes used
to find velocity when acceleration and
time are known. Another form of this
equation is v = v_0 + a*del_t. In this second
form of the equation, the function of the
term v_0 is to:
A. indicate that the equation is valid
only for an object that starts at rest.
B. determine the time at which
velocity is equal to zero.
1. A ball is thrown with an initial velocity of 20 m/s at an angle of 30°
above the horizontal. What is the instantaneous vertical velocity of
the ball when it is 5.1 m above the release point? (g = 9.8 m/s^2)
A. 0.2 m/s
B. 6.6 m/s
C. 10 m/s
D. 17 m/s
A. What’s the speed of an electron in a cathode ray tube if the electric field and magnetic field are of unit strength in SI unit? Calculate magnetic force experienced by the electron. 4 marks
B. Derive the formula for magnetic field produced by an infinitely long straight conductor. 4 marks
(c) Fission of U – 235 nucleus releases 200 MeV of energy. Calculate the fission rate (i.e. no. of fissions per second) in order to produce a power of 320 MW.
Q 10:
(a) What’s the ratio of the shortest wavelength of Balmer series to the shortest wavelength of the Lyman series?
(b) What are the (i) energy (ii) magnitude of momentum, and (iii) wavelength of the photon associated with spectral emission of H-atom transition; n=3 state to n=1 state?
Question 1
Answer all question briefly and to the point.
(i)
Explain the statement ‘relative permittivity of water is 81’.
(ii)
Draw (at least three) electric lines of force due to an electric dipole.
(iii)
Find the value of resistance X in the circuit below so that the junction M and N are at the same potential.
(ix)
A ray LM of monochromatic light incident normally on one refracting surface AB of a regular glass prism ABC emerges in air from the adjacent surface AC as shown in Figure. Calculate the refractive index of the material of the prism.
SECTION A
(Answer any two questions)
Question 2
(a)
With the help of a labeled diagram, obtain an expression for the electric field intensity ‘E’ at a point P in broad side position (i.e. equatorial plane) of an electric dipole.
Question 3
(c)
(i) State any two differences between a moving coil galvanometer and a tangent galvanometer.
(ii) What is the use of a Cyclotron?
SECTION C
(Answer any two questions)
Question 8
(a)
Electrons, initially at rest, are passed through a potential difference of 2 kV. Calculate their:
(i) Final velocity and
(ii) de Broglie wavelength
