Kamis, 10 September 2020

MODEL LAPORAN PRAKTIKUM FISIKA

PERCOBAAN CERMIN SFERIK

 

I.       Tujuan

·         Memahami sifat bayangan yang dibentuk oleh cermin sferik

·         Menentukan jarak titik fokus cermin sferik

 

II.    Alat

·         Bangku optik

·         Senter

·         Benda ( sebagai objek )

·         Cermin cekung dan cermin cembung

·         Mistar panjang

 

III. Teori

Cermin memiliki tampilan bagian yang mengkilap dan cermin memiliki tampilan cermin datar, cermin cembung dan cermin cekung ( merupakan cermin sferik ). Cermin sferik memiliki bentuk lengkung dan memiliki jari – jari.

 

Cermin cekung :

Aturan sinar istimewa pada cermin cekung :

(1)   Sinar datang sejajar sumbu utama akan dipantulkan melalui titik fokus

(2)   Sinar datang menuju titik fokus akan dipantulkan sejajar sumbu utama

(3)   Sinar datang menuju titik pusat kelengkungkan akan dipantulkan kembali melalui titik pusat

      kelengkungan

 

 


 

                         

 

Cermin Cembung

Aturan sinar istimewa pada cermin cembung :

(1)   Sinar datang sejajar sumbu utama akan dipantulkan seolah – olah melalui titik fokus

(2)   Sinar datang menuju titik fokus akan dipantulkan sejajar sumbu utama

(3)   Sinar datang menuju titik pusat kelengkungan akan dipantulkan seolah – olah melalui titik

       pusat kelengkungan


 

 

 



                             Gambar 2. Aturan sinar istimewa pada cermin cembung

 


 




IV. Prosedur Percobaan

·         Susunlah rangkaian seperti gambar di bawah ini


 


 

  • Setelah rangkaian percobaan selesai anda rangkaikan, selanjutnya anda mengikuti petunjuk yang diberikan guru untuk menentukan letak benda dari cermin.
  • Nyalakan sumber cahaya, kemudian anda melakukan pencarian bayangan, bayangan yang jelas ditangkap layar merupakan jarak benda yang sesungguhnya.
  • Ukurlah jarak bayangan yang anda dapat lalu isilah tabel percobaan
  • Selesai anda mengambil data dan mengisi tabel pengamatan, selanjutnya anda melakukan anlisa sesuai dengan pengarahan yang diberikan guru.  

 

V.    Data Percobaan

 

Tabel Pengamatan cermin sferik

No. 

Percobaan

Jarak benda

s (cm)

Jarak bayangan

s’(cm)

Perbesaran bayangan M

Sifat 

bayangan

T

P

T

P

1

 

 

 

 

 

 

2

 

 

 

 

 

 

3

 

 

 

 

 

 

4

 

 

 

 

 

 

5

 

 

 

 

 

 

6

 

 

 

 

 

 

 

 

VI.  Kesimpulan

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DATA PERCOBAAN

 

I.          JUDUL PERCOBAAN               : ..........................................................................................

 

II.        TANGGAL PERCOBAAN         : ..........................................................................................

 

III.     KELAS                                       : ..........................................................................................

 

IV.     KELOMPOK                              : ..........................................................................................

 

V.       ABSENSI                                   : ..........................................................................................

 

Praktikan yang hadir :

 

1.      .................................................. (      )                     6.   ....................................................... (     )

 

2.      ............................................... (      )                        7.   ....................................................... (     )

 

3.      ............................................... (      )                        8.   ....................................................... (     )

 

4.      ............................................... (      )                        9.   ....................................................... (     )

 

5.      ............................................... (      )                        10. ....................................................... (     )

 

 

 

Praktikan yang tidak hadir :

 

1.      .................................................. (      )                     4.   ....................................................... (     )

 

2.      ............................................... (      )                        5.   ....................................................... (     )

 

3.      ............................................... (      )                        6.   ....................................................... (     )

 

 

VI.     DATA PENGAMATAN

 

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Medan,     

Asisten Praktikum

 

 


 

                                                                                    (                                               )    


 Penulis : Parulian Simorangkir
Jabatan : Kepala Lab. Fisika SMA WR Supratman 2 Medan 





SERI - 1 SOAL DAN PEMBAHASAN ENERGI SMP

Contoh 01 :

Sebuah mobil melaju dengan kecepatan 20 m/s. 

Maka daya mesin jika gaya dorong mesin mobil 450N ?

Pembahasan :


Dik : 
kelajuan, v = 20 m/s
Gaya, F = 450 N

Dit : daya mobil, P = … ?

Peny :

P = F x v

P = 450 x 20

P = 9000 watt

P = 9,0 kW



Contoh 02
lift ke ketinggian 50 meter dalam waktu 20 detik. 
( percepatan gravitasi bumi, g = 10 N/kg )
 
Pembahasan
Sebuah lift barang memiliki massa 2 000 kg. 
Berapakah daya yang diperlukan untuk menaikkan

Dik : 

massa, m = 2 000 kg  ; g = 10 N/kg
Tinggi, h = 50 meter 
Waktu, t = 20 detik

Dit : 

daya oleh lift, P = … ?

Peny :

Langkah 1 : 

carikan nilai EP

EP = m.g.h
EP = 2000 x 10 x 50
EP = 1 000 000 J 



Contoh : 03

Seorang anak beratnya 350 N  menaiki tangga yang tingginya 

7 m dalam waktu 40 s.Maka daya yang dilakukan anak tersebut

 … ( dalam satuan watt )

A.    2000

B.    125

C.   61,25

D.   12,5

 

Pembahasan :

Langkaha 1

carikan EP

EP = m.g . h
EP = w.h
EP = 350 x 7 = 2450 J 



Contoh : 04
Sebuah pesawat dengan daya 25 watt melakukan usaha 
sebesar 500 J. Ini berarti pesawat tersebut bekerja 
selama ........ s.
A.    12 500
B.    475
C.   25
D.   20

 

Pembahasan

Dik : 

usaha, W = 500 J

Daya, P = 25 watt

Dit : waktu, t = … ? 






CONTOH DAN PENYELESAIAN SOAL HIMPUNAN (2)

 Cara mendekatkan pemahaman siswa akan himpunan dapat dilakukan dengan berbagai model dan tipe.  Saya sendiri menggunakan model ini, dengan harapan siswa tersebut dapat terbantukan. 








P.enulis : Parulian Simorangkir








CONTOH SOAL DAN PENYELESAIAN OPERASI HIMPUNAN

 








P.enulis : Parulian Simorangkir 
SMP WR SUPRATMAN 2 MEDAN 






Rabu, 09 September 2020

CONTOH DAN PENYELESAIAN JUMLAH DAN SELISIH DUA SUDUT

   

  















P.enulis : Parulian Simorangkir 





















TRIGONOMETRI JUMLAH DAN SELISIH DUA SUDUT (Part 2 )

 

 







P.enulis : Parulian Simorangkir 












TRIGONOMETRI JUMLAH DAN SELISIH DUA SUDUT (Part 1)

 

A.   Rumus Jumlah dan Selisih Dua Sudut

 

Kompetensi Dasar :

3.2. Membedakan Penggunaan Jumlah dan Selisih Sinus dan Cosinus

4.2. Menyelesaikan masalah yang berkaitan dengan rumus jumlah dan selisih Sinus dan

       Cosinus

 

Rumus  Sinus, Cosinus, dan tangen dua sudut adalah  sebagai berikut


      

      


  

 B.   Rumus Sudut Rangkap

 Sudut rangkap 





    

 

 


 Penulis : Parulian Simorangkir


























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