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# What Is Life

• Date Submitted: 11/03/2011 08:38 PM
• Flesch-Kincaid Score: 58.1
• Words: 632
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Pentagon International College Dashain Homework assignment- Grade XII (Science) The Dashain/ Deepawali and Chhath is the long vacation for the students. Institution understands that the students must keep in touch with studies. It is the great time for them to practice and cover the units taught. Therefore, Dashain Homework assignment for grade XI students is provided to update your knowledge. Students are informed to complete and submit on Kartik 23, 2068 as mentioned in the college calendar. DO NOT WASTE YOUR PRECIOUS TIME. The marks of Dashain Homework assignment will be added in 2 nd term exam. Make separate copy for each subject. Physics: Dashain vacation home work for grade XII-2068 Solve the following numerical problems: 1. If a detonator is exploded on a railway line, an observer standing on the rail 2 m away hears two reports. Why is this so? What is the time interval between these two reports? ( Youngs modulus of steel = 2x1011 N m-2, density of steel = 8000 kg m-3, density of air = 1.4 kg m-3 2. = 1.4, Atmospheric pressure = 105 N m-2.

In the Bohr model of hydrogen atom, the electron revolves around the nucleus in a circular orbit of radius 0.53 A 0, at 6.8x1015 rev/s, find the equivalent (i) current (ii) magnetic field at a point on its axis O.53 cm away from the center and (iii) magnetic moment due to orbital motion of the electron.

3.

An electron with the velocity of 107 m/s enters a region of uniform magnetic field of 0.1 T at an angle of 250 with the direction of magnetic field. By resolving its velocity, find the pitch of its helical path.

4.

A current of 5 A is passing through a metallic wire of cross-sectional area 4x10-6 m2. If the density of the charge carriers in the wire is 5x1026 m-3, find the drift speed of the electrons.

5.

A rod of length

rotates with small but uniform angular velocity