# Physics

0.0 / 5

- Created by: autopianjew
- Created on: 26-06-17 14:32

Define the term: Effeciency

Energy efficiency is a measure of how well a device transfers energy into the form we want.

1 of 43

What is the calculation for effeciency?

efficiency = ( useful energy transferred ÷ energy supplied ) × 100

2 of 43

Can effeciency ever be 100 of a product, and why?

No as some of it is always lost to watched energy (heat, sound).

3 of 43

How can efficiency in mechanical systems be increased?

Making it more aero-dynamic; less heat loss; more lubricated, reduce friction

4 of 43

What is a U Value?

How much thermal energy transfers each second

5 of 43

What does a High U-Value show?

More energy transfer every second meaning it loses heat quicker.

6 of 43

What do resistors in Series circuits do to form a greater resistance?

Add together

7 of 43

What do resistors in a Paralel circuit do to reduce total resistance?

Combine together

8 of 43

What is the Specific heat capacity of a material mean?

The amount of energy required to raise 1KG of the material by 1C.

9 of 43

Equation for Energy and their units?

Energy (J) = Mass (KG) * SHC (J/KHc) * Change in temp (C)

10 of 43

What do large U-Values allow?

They allow heat energy to flow more quickly.

11 of 43

What effect would reducing the U-Value of a insulator have?

Makes it more efficient at maintaining a temperature and cheaper to insulate/run

12 of 43

What is the equation for Resistance?

V = I*$

13 of 43

In resistance, what does V stand for? And it's unit?

Potential Difference (V)

14 of 43

In resistance, what does I stand for? And it's unit?

Current (A)

15 of 43

In resistance, what does R stand for? And it's unit?

Resistance (Ohms)

16 of 43

The current in a series circuit is what through each component?

The same

17 of 43

The current in a parallel circuit is the sum of the current in ?

In the seperate branches

18 of 43

How is the P.D in a series circuit spread?

It's shared

19 of 43

What is the P.D in a paralel circuit like in each branch of the circuit?

The same

20 of 43

Unit for Charge?

In Coulombs, C

21 of 43

Charge (Q) = ?

Charge (Q) = Current (I) (in Amps) * Time (t) (in Seconds)

22 of 43

In parallel circuits the current is ____ through every component

The same

23 of 43

In series circuits the voltage across each components does what to the battery voltage?

Adds up to the battery voltage

24 of 43

What does the voltage of each component in a series circuit depend on?

Depends on it's resistance

25 of 43

What will never change in a series circuit?

Amps

26 of 43

If a objects velocity changes, what also will change?

It's momentum.

27 of 43

Is acceleration a Vector or scalar?

Vector

28 of 43

What is Scalar?

Only magnitude

29 of 43

What is Vector?

Both direction and magnitude (size)

30 of 43

What does displacement mean?

Distance from orginal start point

31 of 43

No resultant force = ?

No change in momentum

32 of 43

What does the acceleration of a object depend on? (2 things)

The resultant force applies and the mass of the object

33 of 43

What is Enertia?

Something which has a resistance to motion

34 of 43

Momentum is ____

Converved

35 of 43

An increase in stopping distance is also a increase of?

Impact time + Time of collision

36 of 43

What is Impact force equal to?

The rate of change of momentum

37 of 43

Increasing the time of an impact will do what?

Reduce the impact forces (meaning it lasts longer)

38 of 43

What happens when temperature increases on a resistor of a conductor?

Resistance increases of the conductor

39 of 43

In low temperature's, the resistance of a thermistor is high meaning?

Little current can flow through

40 of 43

At high temperatures, the resistance of a thermistor is low, how does this effect current?

More current can flow through

41 of 43

In the dark; what is the resistance of a LDR like? And what does this mean?

High so little current can flow through

42 of 43

In the bright light, what is the resistance of a LDR like? And what does this mean?

The resistance of LDR is low, and more current can flow through it.

43 of 43

## Other cards in this set

### Card 2

#### Front

What is the calculation for effeciency?

#### Back

efficiency = ( useful energy transferred ÷ energy supplied ) × 100

### Card 3

#### Front

Can effeciency ever be 100 of a product, and why?

#### Back

### Card 4

#### Front

How can efficiency in mechanical systems be increased?

#### Back

### Card 5

#### Front

What is a U Value?

#### Back

## Related discussions on The Student Room

- Family cooking makes me sick!!! »
- biology - mock practise »
- Help about womens eggs »
- I'm dumb, I need help »
- Is egg a vegetable? »
- I'm chasing several idealistic dreams - Ask Me Anything! »
- Thoughts on egg donation? »
- Killing giant African land snail eggs »
- A ducking kid threw an egg at my window »
- The Great Gatsby »

## Similar Economics resources:

0.0 / 5

5.0 / 5 based on 1 rating

0.0 / 5

0.0 / 5

0.0 / 5

0.0 / 5

2.0 / 5 based on 4 ratings

2.0 / 5 based on 1 rating

## Comments

No comments have yet been made