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Neco physics obj and theory answers here


Satellite an artificial body placed in orbit round the earth or
another planet in order to collect information or for

Cosmic (ii) Magnetic field

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.

2a) do the graph yourself

D = √(x2 - x1)^2 (y2 - y1)^2
= √(-3-5)^2 (-4-(-2))^2.
= √64 36
= 10unit

Yes fractional force depend on the nature of the surface

Walking without fractional force depending on the nature of the
surface, there would be slipping and skidding

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

Work done is defined as the minimum energy required for electrons
to be liberated from the surface of a metal when light is incident

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 }

85 - x/ 50 - x = 100 - 0/40 - 0
4(85 - x) = 500 - 10x
-4x 10x = 500 - 340
6x = 160
X= 26.67oc
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

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

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.

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.

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.
Artificial Radioactivity this is an ordinary material,not normally
radioactivr is made radioactive by bombarbing it with radioactive

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

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

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.


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
(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

Convex mirror or Converging mirror
* It produce an erect image and has a wide range of view

A piano have strings of different lenght so that it can produce
different of sound
F = k/L .... Where F is frequency, L is length

*choose two
- Temperature
- Humidity
- frequency of sound in air
- wavelength of sound in air

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

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.

Flat Plate Solar Collector is the key part of the flat plate
solar water heater. It consists of absorber, cover glass, insulation,
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

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.

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Posted By On 01:14 Wed, 18 Jun 2014

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