Just turn down the heat.
For The conventional oven, there would be convection that heats and re-heats the air. As the heat rises, it peaks and cools, then drops back down just to be heated up again.
Perhaps the knob is on upside down? On my oven the knobs are removeable, you just pull it off.
to heat up the toast .
a solar cooking oven
the oven indicator light stays on and the temperature light but i turn the oven nob on and the oven heat up then i turn off . it gos out tell the temperature cools down. then it come back 0n.
In small oven heaters.
i think when you heat it up a oil balloon i think it gonna melts.
This would depend on the manufacter of the oven and what temperature you have it set to but it can typically take 20 - 30 minutes to fully heat up.
It means open up the can, put the food or whatever inside into a saucepan then light the cooker and heat it. You can heat it up in microwave oven but in my opinion, food is not so good when heated in oven.
If it's an electric oven, the fuse may have blown, or the circuit breaker may have tripped. Do you know where your household fusebox/ breaker box is?
The oven doesn't heat up. The air inside stays at room temperature (although that would be difficult to measure). What heats up is the substances you place in the oven that absorb 2.5 GHz radio energy effectively ... mostly water and fats in foods.