Question

Q.

sebuah cermin cekung mempunyai jari jari kelengkungan 10 cm, tinggi benda 2 cm, dan terletak 15 cm di depan cermin. Tentukan :
• Jarak fokus (F)
• Jarak bayangan (S')
• Perbesaran bayangan (M)​

Answer 1

A.

f = 1/2 × r

f = 1/2 × 10

f = 10/2

f = 5 cm

B.

1/s' = -1/s + 1/f

1/s' = -1/15 + 1/5

1/s' = -1/15 + 3/15

1/s' = 2/15

s' = 15/2

s' = 7,5 cm

C.

M = s'/s

M = 7,5/15

M = (7,5 ÷ 7,5)/(15 ÷ 7,5)

M = 1/2 Kali Diperbesar

Answer 2

•Alat optik

Dik:

- R = 10cm

- h = 2cm

- s = 15cm

Dit:

- f = ?

- s' = ?

- M = ?

Jawab:

• Mencari jarak fokus

f = ½R

f = ½ × 10cm

f = 5cm

• Mencari jarak bayangan

1/f = 1/s + 1/s'

1/5 = 1/15 + 1/s'

1/5 - 1/15 = 1/s'

3/15 - 1/15 = 1/s'

2/15 = 1/s'

s' = 15/2

s' = 7,5cm

• Menentukan perbesaran bayangan

M = |s'/s|

M = |7,5/15|

M = ½kali