Answer:
The position is 8.18cm from the mirror.
Nature is b=virtual
Size is 1.82cm
Explanation:
Note that for a convex mirror, the image distance and the focal length are negative;
Given
Object height H0 = 4cm
object distance u = 18cm
Radius of curvature R = 30cm
Since f = R/2
f = 30/2
f = -15cm
Recall that:

Since the image distance is negative, this shows that the image is a virtual image.
To get the size:

Escape velocity is the speed that an object needs to be traveling to break free of a planet or moon's gravity well and leave it without further propulsion. For example, a spacecraft leaving the surface of Earth needs to be going 7 miles per second, or nearly 25,000 miles per hour to leave without falling back to the surface or falling into orbit.
Answer:
Decreases by
times
Explanation:
The intensity of a sound is defined as the energy of the sound that is flowing in an unit time through the unit area which is in the direction that is perpendicular to the direction of the sound waves movement.
The intensity of energy is described by the inverse square law. It states that the intensity varies inversely with the distance square of the distance.
In other words, the sound intensity decreases as inversely proportional to the squared of the distance. i.e. 
In the context when the distance was 3 m, the intensity of the sound was = 
But when the distance became 6 cm or 0.06 m, the sound intensity decreases by = 
=
times
This means that there is same current flow in both the circuit, or the circuit one has twice the power of circuit two.
According to ohm's law, the resistance is given as
I=V/R
Since the circuit one has twice the voltage, and resistance
I1=I2