Answer:
Explanation:
The sensor contains an LDR which has a resistance of 10kohlms in daylight and 100kohlms in the dark.
If the resistor in the circuit is 1 megaohlm, the total resistance in daylight and darkness will be 1.01 megaohms and 1.1 megaohlms.
The percentage difference = (1.1-1.01)/1.1*100% = 8.18%
If the resistor in the circuit is 25 kohlm, the total resistance in daylight and darkness will be 35 kohms and 125 kohlms.
The percentage difference = (125-35)/125*100% = 72%
With the input p.d to the sensing circuit fixed at 12 v, the sensing current will change according to the total resistance. A 72% difference is much more detectable. So the 25 kohm resistor is the better choice.
Answer:
2.25 N upwards
Explanation:
Answer:
800 N/C to the right
Explanation:
The equation that relates force on a charge, electric field and charge is
where
F is the force acting on the charge
q is the charge
E is the electric field
In this problem, we have
is the electric field
is the charge
Substituting into the formula, we find the force
Concerning the direction:
- The electric field and the force have same directions if the charge is positive
- The electric field and the force have opposite directions if the charge is negative
Here the charge is negative, so the electric field has opposite direction to the force: therefore, it must be upwards.
Shield volcanos have the most predictable eruptions.
Answer:The higher up an object is the greater its gravitational potential energy. The larger the distance something falls through the greater the amount of GPE the object loses as it falls. As most of this GPE gets changed into kinetic energy, the higher up the object starts from the faster it will be falling when it hits the ground. So a change in gravitational potential energy depends on the height an object moves through.
Explanation: Lifting an apple up 1 metre is easier work than lifting an apple tree the same height. This is because a tree has more mass, so it needs to be given more gravitational potential energy to reach the same height.
A vector has a size and a direction. The size is called the magnitude of the vector.
