(i) Hexagonal close-packing and cubic close-packing?
Ans: A 2-d hexagonal close-packing contains two types of triangular voids (a and b) as shown in figure 1. Let us call this 2-D structure as layer A. Now, particles are kept in the voids present in layer A (it can be easily observed from figures 2 and 3 that only one of the voids will be occupied in the process, i.e., either a or b). Let us call the particles or spheres present in the voids of layer A as layer B. Now, two types of voids are present in layer 
(c and 
). Unlike the voids present in layer 
Leteriftid
Ans: The given solids are classified as follows:
– Ionic (ii) Ammonium phosphate 
– Metallic (viii) Brass, (ix) Rb
– Molecular Tetra phosphoursdecoxide 
– Covalent (network) (iii) SiC, (vii) Graphite, (xi) Si
– Amorphous (vi) Plastic.
How you distinguish between the following pairs of terms:
How you distinguish between the following pairs of terms:
.
)
west of the geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points above the horizontal. The horizontal component of the earth’s field is measured to be 
Specify the direction and magnitude of the earth’s field at the location.At a certain location in Africa, a compass points 
and 
and 
in the same direction are separated by a distance of 
. Estimate the force on a 
section of wire A.
wire carrying a current of 
is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be 
. What is the magnetic force on the wire?
and making an angle of 
with the direction of a uniform magnetic field of 
. What is the magnitude of the field 
at a point 
from the wire?
-turns carrying current 
.
is at distance 
from the wire. Find the force acting on the electron if its velocity is directed towards the wire.