Answer:
Explanation:
When teacher falls into the cliff then she shout for Help at the same time
so here we know that sound will go down and reflect back up
so here in 3 s distance traveled by the sound
now in the same time the distance that teacher will fall down is given as
now total distance traveled by teacher and sound in 3 s
this total distance must be equal to twice the height of the cliff
Answer: A voltmeter must have a high resistance where as an ammeter must have a low resistance.
Explanation:
A voltmeter is a device which is connected in parallel to the component across which voltage needs to be measured. In a parallel circuit voltage drop is same at the nodes. The parallel connection must not offer easier path for current to divert from the main circuit and travel. Thus, a voltmeter must have high resistance.
On the other hand, an ammeter which is used to measure current in the circuit must have low resistance as it is connected in series. It should not offer resistance as it would reduce the actual current and measurement would be inaccurate.
Answer:
0.03 A
Explanation:
From the question given above, the following data were obtained:
Voltage (V) = 12 V
Resistor (R) = 470 Ω
Current (I) =?
From ohm's law, the voltage, current and resistor are related by the following formula:
Voltage = current × resistor
V = IR
With the above formula, we can obtain the current in the circuit as follow:
Voltage (V) = 12 V
Resistor (R) = 470 Ω
Current (I) =?
V = IR
12 = I × 470
Divide both side by 470
I = 12 / 470
I = 0.03 A
Thus, the current in the circuit is 0.03 A
A) lithium and beryllium
Explanation:
From the given row on the periodic table, only lithium and beryllium will conduct electricity.
What makes a substance able to conduct electricity?
- The presence of free mobile electrons and in some, ions allows them to carry electric currents.
Metals are generally known to be good conductors of heat and electricity. This is because, metals have a large pool of electrons i.e free mobile electrons. They are electropositive with a large size and readily release their electrons for conduction.
Lithium and Beryllium are in the metallic block on the periodic table.
Learn more:
Metals brainly.com/question/2474874
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