A Question a Day (series) Q3 Reply

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.


A Question a Day (series) Q2 Reply

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 More…

Physics Class Test, XII {PU/ISc/ICSE/CBSE} 2

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 More…

Physics Midterm for ISc-II (ICSE) [also good for CBSE/PU-II] Reply

(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? More…

ISC Board Question Paper Class XII – 2009 (ICSE) Reply

(vi). Write an equation of Lorentz force F acting on a charged particle having charge q moving in a magnetic field B with a velocity v in vector form.

(vii). What is the value of power factor in a series LCR circuit at resonance?

(viii). An a.c. generator generates an emf ‘e’ given by : e = 311 Sin (100 πt) volt. Find the rms value of the emf generated by the generator.

(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. More…

Physics midterm exam, class XII (ISc-II) ICSE (also good for PU/CBSE) Reply

Question 11

Describe the Thomson’s e/m experiment by mutually perpendicular set-up of electric field and magnetic field; E and B. Derive in necessary steps how e/m would be determined by this set up from various known parameters such as E and B values.

Question 12

Threshold wavelength of Tungsten is 2400 Angstrom. Tungsten is illuminated by a light of wavelength 1600 Angstrom. Whats the value of work function, maximum kinetic energy of electrons and stopping potential. Describe the ideas of Photoelectric effect. Who discovered photoelectric effect? Which scientist successfully explained this effect? More…