1. What is the primary function of the physical layer?
a) Transmitting digital signals
b) Transmitting analog signals
c) Moving data as electromagnetic signals over a transmission medium
d) Converting digital signals to analog signals

2. Which type of data is continuous?
a) Digital data
b) Analog data
c) Binary data
d) Discrete data

3. How does a digital clock represent time?
a) With continuous movement
b) With discrete states
c) By continuous variations
d) By changing frequencies

4. What characteristic distinguishes analog signals?
a) Discrete voltage levels
b) Limited defined values
c) Infinitely many levels of intensity
d) Rapid changes between high and low states

5. In digital signals, what represents binary data?
a) Continuous curves
b) Rapid oscillations
c) Discrete voltage levels
d) Analog modulation

6. What is the primary cause of transmission distortion?
a) Attenuation
b) Noise
c) Distortion
d) Impulse noise

7. How is noise diagrammatically represented?
a) As a flat line
b) As random spikes
c) As sine waves
d) As square waves

8. Which distortion primarily affects composite signals?
a) Attenuation
b) Thermal noise
c) Distortion
d) Shot noise

9. What causes attenuation in a signal?
a) Impedance matching
b) Low-pass filtering

c) Environment resistance
d) Rapid oscillations

10. Which technique is used for digital-to-digital conversion?
a) Block coding
b) PCM
c) Delta modulation
d) Line coding