Seafarer's board exam

Question: 

The interval between the sun’s upper limb being in the horizon and its center being 12° below is called: 

A. Nautical twilight 
B. Astronomical twilight 
C. Observational twilight 
D. Civil twilight


Answer:   A. Nautical twilight 

Question: 

The dividing meridian between zone descriptions +4 and +5 is _____. 

A. 75° 00’ E 
B. 60° 00’ E 
C. 67° 30’ W 
D. 60° 30’ W


Answer:    C. 67° 30’ W 


Question: 

Physical checks of gyro, azimuth circle and pelorus include the following, EXCEPT: 

A. align peloruses with fore-and-aft line of the ship 
B. synchronize gyro repeaters with master gyro 
C. ensure azimuth circle and peloruses are in good condition 
D. align the compass north to the fore and aft line of the ship



Answer:    A. align peloruses with fore-and-aft line of the ship 


Question: 

The bending of a wave as it passes an obstruction is called _________. 

A. persistence 
B. refraction 
C. diffraction 
D. attenuation


Answer:   C. diffraction