Postingan
Contoh Soal Fisika Tentang Bab Alat Optik Beserta Pembahasannya
1.Someone is only able to see objects clearly
at the furthest distance of 1,5 meters. The lens strength of eye glasses which
must be used is ... (medium)
a.
½
dioptri
b.
2/3
dioptri
c.
-1/2
dioptri
d.
-2/3
dioptri
e.
-1
dioptri
Solution
:
PR
= 1,5 m / 150 cm
S’ = -PR
F = -150 cm
(D)
2.
A
Man observes his KTP using loop with
strength of 10 dioptries. If he has punctum proximum 30 cm and want to obtain
the maximum angular magnification. The distance of KTP must be placed to the
loop is... (medium)
a.
3,5
cm
b.
4,5
cm
c.
5,5
cm
d.
6,5
cm
e.
7,5
cm
Solution
:
Pp=
30cm, f = 
= 
= 
=
4
(E)
3.
A
microscope is used to observe an object at distance of 1,5 cm. If the focal
length of the objective and ocular lens each is 1 cm and 2,5 cm and the eye is not in accomodation. The
lenght of microscope is ...... (medium)
a.
3,5
cm
b.
4,5
cm
c.
5,5
cm
d.
6,5
cm
e.
7,5
cm
Solution
:
Sob = 1,5 cm
Fob = 1 cm
Fok
= 2,5 cm
3
cm
4.
Temperature
of the Celsius and Fahrenheit scale show the same value in ... (medium)
a.
-40°
b.
-50°
c.
-60°
d.
-70°
e.
-80°
Solution
:
C
= 
C=F jadi C = 
4C
= -160 →
C = -40 °C
5.
A
hollow ball is made of bronze ( α x 10-6/°C). At temperature 0°C its
radius is 1 m. If the ball is warmwd up to 80°C. The area incremen of the
ball’s surface is ... (difficult)
a.
1.12
x 10-2 
b.
1.15
x 10-2
c.
1.2
x 10-2
d.
1.5
x 10-2
e.
1.25
x 10-2
Solution :
= (4
= (4
= 11520 x 10-6
= 1.15 x 10-2 (B)
(B)
6.
The
water 100 grams in temperature 20°C mixed with the water 50 grams in the
temperate 80°C. The mixture temperature of both water is .....( c water = 1
cal/g) (medium)
a.
40°C
b.
50°C
c.
60°C
d.
70°C
e.
80°C
Solution
:
M1 = 100g, t1=
20°C
M2 = 100g, t2=
80°C
Qterima = m1.
C (tc-t1)
= 100.1 (tc-20)
= 100 tc -2000
Qlepas = m1.
C (t2-tc)
= 50.1. (80-tc)
= 4000 - 50tc
Qterima = Qlepas
100 tc -2000
= 4000 - 50tc
150 tc = 6000
tc = 40°C (A)
7.
A
wall has the relative constant temperature of 25°C in outdoor air temperature
of 18°C. The dissipation head in 3 hours because of head convection if the wall
area 15m2 and h= 3.5 J/s m2K is ..... (medium)
a.
36,67
x 105 J
b.
37,69
x 105 J
c.
39,69
x 105 J
d.
36,69
x 105 J
e.
39,67
x 105 J
Solution :
h
= 3.5 J/s m2K
A
= 15m2
°C / 7 K
3
jam = 10800 s
= 3.5 J/s m2K . 15m2.
7 K . 10800 s
= 39,69 x 105 J (D)
8.
A
voltmeter possesses a measure limit of 100 mV with internal resistance of 1000
ohms. The front resistance that be assemblies in order for the voltmeter to
measure voltage up to 10 V is..... (medium)
a.
77.000
b.
88.000
c.
99.000
d.
100.000
e.
111.000
Solution :
V
= 100mV = 0,1V
V
= 1 V
Rv
= 1000 ohm
n
= 
Rd
= (n-1) Rv
= (100-1)1000 ohm
= 99.000 ohm (C)
9.
An
electrical resistance of 10 is inserted into a water of 100 gr at 20°C. If the
resisteance is given a voltage differense of 50 V for 1 minute. The final
temperature if the specificheat of the water is cal/g °C is ..... (difficult)
a.
55
°C
b.
56
°C
c.
46
°C
d.
66
°C
e.
45
°C
Solution
:
R
= 10 C = 1 cal/g
°C
M = 100gr t = 1 minute
V = 50 V T1 = 20 °C
=
15 x 103 J =15 x 103 x 0,24 kalori = 3.6 x 103 kalori
=
T1 + 
=
20 +36
(B)
10. The temperature of a n
object is 127
and its surface width is 12 m2 for
1 minute. The energy radiated by the object if its considered to be absolutely
black is... (medium)
and its surface width is 12 m2 for
1 minute. The energy radiated by the object if its considered to be absolutely
black is... (medium)
a.
174.104
b.
175.104
c.
176.104
d.
177.104
e.
173.104
Solution
:
T = 127 + 273 = 400K
W = e.
= 5,7 x 10-8 x (400)4
= 1.459,2 watts/m2
E = W x A x t
= 1.459,2 x 12 x 60
= 175.104 J (B)
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