physics anwer

PHYSICS ANSWERS
VERIFY PHY OBJ
1-10. ADCDEEAEDE
11-20. EDABDDABCD
21-30 EECCECBDAA
31-40 AABAACCBBD
41-50 CDBCEDACBD
51-60 CCCBDDDDCE
1a)
Satellite an artificial body placed in
orbit round
the earth or
another planet in order to collect
information or
for
communication.
1b)
Cosmic (ii) Magnetic field
1c)
The artificial satellite is first launched
to space
which produces
visual signals to Tv stations and its
further
transmitted or relayed
to individual house and hence, the
2014 Brazil
world cup be viewed
2b)
D = √(x2 - x1)^2 + (y2 - y1)^2
= √(-3-5)^2 + (-4-(-2))^2.
= √64+36
= 10unit
3a)
Yes fr-al force depend on the nature of
the
surface
3b)
Walking without fr-al force depending
on
the nature of the
surface, there would be slipping and
skidding
4a)
The work done is the area of the
rectangle
* Area of rectangle = L x B
Work done (I) 2F^1 x d^1 = 2F^1d^1 ( ^
means
raise to power)
Work done (ii) F^1 x d^1 = F^1d^1
Difference in work done = 2F^1d^1 -
F^1d^1 =
F^1d^1Nm
4ii)
Work done is defined as the minimum
energy
required for electrons
to be liberated from the surface of a
metal
when light is incident
onit
b)
E= hf but C= F/|, F = C//| , E= hc//|
E= 5.5 x 10^-9J, /|= 6.6x10^-34 x
3x10^8/5.5
x 10^-9
/|=3.6x10^-17 {where J is joule, /| is
lander }
5a)
85 - x/ 50 - x = 100 - 0/40 - 0
4(85 - x) = 500 - 10x
-4x + 10x = 500 - 340
6x = 160
X= 26.67oc
6)
V = 3x10m/s
From the diagram, T=12s(time taken
to
complete one cycle)
6aii) V=F/|, F=1//| , /|= VT { where /| is
lander }
/|=3x10^3 x 12 = 3.6x10^4m
6aiii) F=1/t = 1/12= 0.083Hz
8a)
E=2.0v, r=1ohm, R=?, V=1.92v
From E= I(R+r) also, V=IR, I=V/R
E= V/R(R+r)
2R= 1.92R + 1.92
2R - 1.92R = 1.92
0.08R = 1.92
R = 1.92/0.08 =24ohms
9a.)
The basic unit of measure of electricity
is
known as the Watt.
One thousand Watts are called a
kilowatt.
OR .the unit is kilowatt per
hour (kwh)/ def
1kwh is the energy consumed by
power
consumption of 1kilowatt during
1hour.
(9b)
Two Advantages At high voltages
(i)to ruduce the energy loss in long-
distance
transmission,
(ii)also for greater efficiency during
long
distance transmissiön.
two Advantages at Low Current
(i)to accomodate the use of low using
electrical
appliances,
(ii) to promote even distribution of
current.
10a)
Natural radioactivity is the
spontaneous
distingration of the
nucleus of an atom during which alpha
particle
or beta particle,or
gamma rays or a combination of any
or all the
three and heat (or
energy) are released.
While
Artificial Radioactivity this is an
ordinary
material,not normally
radioactivr is made radioactive by
bombarbing
it with radioactive
particles.
10b)
Two Uses Of Radioisotopes.
i Radioisotopes are used in medicine as
radiotherapy.
ii. Radioisotopes are used in industry to
study
defects in metals and
welded joints.
iii. Radioisotopes are used in geological
research for radio-dating
11a)
Work function is defined as the
minimum
energy required for
electrons to be liberated from the
surface of a
metal when light is
incident on it
11b)
E= hf but C= f/| , f=C / /|
E= hc / /| , E= 5.5 x 10^-9 J
/| = 6.6x10^-34 x 3x10^8 / 5.5 x 10^-9
= 3.6 x 10^-17m
13a )
A vacuum flask, or thermos, does not
allow
heat transfer by
any of the three ways that heat can
travel. The
silver coating
on the inner bottle prevents heat
transfer by
radiation, and
the vacuum between its double wall
prevents
heat moving by
convection. The thinness of the glass
walls
stops heat
entering or leaving the flask by
conduction. The
case
surrounding the flask provides
additional
insulation.
13aii)
Cork
13b)
Inclined plane (ii) Wheel and axel
13bii) m=6000kg , h=0.25m , L=0.75m
EFF=85-
(I) * V.R of a screw jack = distance
move by
effort/load
30 x 2 x 3.142 x 0.75/0.25
=565.2
(ii) * M.A = Eff x VR/100 = 85 x
565.2/100
M.A = 480.42 = L/E
Effort= L/480.42 = mg/480.42 = 6000 x
10/480.2
E= 124.9N
14a)
Convex mirror or Converging mirror
* It produce an erect image and has a
wide
range of view
14b)
A piano have strings of different lenght
so that
it can produce
different of sound
14bii)
F = k/L .... Where F is frequency, L is
length
14c)
*choose two
- Temperature
- Humidity
- frequency of sound in air
- wavelength of sound in air
14cii)
fo = 220Hz (open pipe)
Ist overtone freq of open pipe = Ist
overtone
freq of closed
2fo cp = 3fo cp
2 x 220/3 = 146.67HZ ( fo cp)
For Closed pipe
V = 4fl , l=V/4f
330/4x146.67 = 0.56m
For Opened pipe
V = 2fl , l = V/2f
330/2x220 = 0.75m
17ai)
1.The absorber is usually a sheet of
high-
thermal-conductivity
metal with tubes or ducts either
integral or
attached. Its surface is painted or
coated to
maximize radiant energy
absorption and in some cases to
minimize
radiant emission.
2.The insulated box, provides structure
and
sealing and reduces heat
loss from the back or sides of the
collector.
17aii)
Flat Plate Solar Collector is the key part
of the
flat plate
solar water heater. It consists of
absorber,
cover glass, insulation,
and
shell.
The metal absorbing plate with
coating is
welded on the red
copper pipe. The cold water or the
medium
liquid is heated
when running through the pipe. The
transparent
cover glass allows
visible light to pass through and blocks
the the
far infrared.
It means the sunlight can pass the
cover glass
and reaches the
absorber to produce heat, but the far
infrared
resulted from the
radiation of heated absorber is blocked
and
kept inside. In this way,
the heat loss is reduced. And the heat-
absorbing efficiency
and the temperature of the absorber
can be
increased. There are
usually three kinds of coatings: black
selective
coating, black
chrome coating and blue tinox
titanium coating.
In areas with winter
temperature above 0 ℃, system of
direct-
heating of cold
water is applicable, but in areas with
winter
temperature below 0 ℃,
the user could input medium liquid in
the
system to heat
cold water indirectly as an alternative.
* Material:
A) Cover glass:transparent toughened
glass
B) Absorber core:copper and aluminum
complex or all copper
C) Pipe: red copper
D) Shell/bracket: aluminum alloy /
galvanized
steel
17b).
One of the main
differences between a telescope and a
microscope is that
A telescope is used
to view things that are far whereas a
microscope is used to view things that
are very near.