Yes and no. For both it depends both on the frequency and dosage received in the exposure. Anything is lethal at high enough dosage!
You may be referring to a wide class of radiation known as ionising radiation. Just which parts of this class that should be considered lethal to people is subject to contraversy. Please see the link.
The lethal dose of lead to humans has been reported to be approximately 450 mg/kg of lead. Testing was done using lead acetate.
visible waves visible waves
humans use waves for things like surfing, body boarding, fishing etc.
In high concentrations CO2 is lethal.
Indeed it does :)
Radiation is lethal to Humans, So no.
No nobody can see any type of waves
1
LOUDNESS
Ultrasonic waves are sound waves with frequencies higher than what humans can hear. Sound waves have frequencies of about 20,000 to 100,000.