An electromagnet is a device in which, by electric current, the magnetic field is produced. Increase the number of coils and increase the strength of the current, thus, increasing the strength of an electromagnet.
The correct option is B.
<h3>What is an electromagnet?</h3>
An electromagnet is a device that consists of a magnetic core encircled by a coil, through which an electric current is carried to magnetize the core.
Wherever controllable magnets are required, such as in devices where the magnetic flux must be adjusted, reversed, or switched on and off, an electromagnet is utilized.
Thus, the correct option is B, increasing the number of coils and increasing the strength of the current.
Learn more about electromagnet, here:
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Answer:
4.79x10¹³s⁻¹
Explanation:
For a first order reaction, the graph of ln k against 1/K follows Arrhenius equation:
lnK = ln A - Ea/RT
<em>Where A is pre-exponential factor, Ea is activation energy, R gas constant and T is absolute temperature</em>
<em />
If you graph ln k = y and 1/T = x:
y = lnA - Ea/R x
<em>Where the slope = -Ea/R</em>
<em>And the intercept = lnA</em>
<em />
To solve the pre-exponential factor:
31.5 = lnA
e^31.5 =
<h3>4.79x10¹³s⁻¹</h3>
s⁻¹ because the reaction is first order.
Answer:
lightning candel is not a physical change.
when you light the candel the wax gets melted which cannot be reversed.
as physical change is that change in which no new substances are formed abd is reversible.
In the option above shattering the plate doesnot make any chemical change likewise cutting hair also doesnot mean so, and boiling water can be condensed.
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Answer is: a. Rubidium (Rb) is more reactive than strontium (Sr) because strontium atoms must lose more electrons.
The ionization energy (Ei) is the minimum amount of energy required to remove the valence electron, when element lose electrons, oxidation number of element grows (oxidation process).
Alkaline metals (group 1), in this example rubidium, have lowest ionizations energy and easy remove valence electrons (one electron), they are most reactive metals.
Earth alkaline metals (group 2), in this example strontium, have higher ionization energy than alkaline metals, because they have two valence electrons, they are less reactive.
Rubidium electron configuration: ₃₇Rb 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s¹; one valence electron is 5s¹ orbital.
Strontium electron configuration: ₃₈Sr 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s²; two valence electrons is 5s² orbital.
Answer:
Indicators show changes in the pH of a solution
Explanation:
A pH meter is an instrument that measures the hydrogen-ion activity in aqueous solutions, indicating the acidity or alkalinity of the solution expressed as pH .The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode, hence the pH meter is sometimes referred to as a potentiometric pH meter. Potentiometric pH meters measure the voltage between two electrodes and display the result converted into the corresponding pH value. The instrument comprises of a simple electronic amplifier and a pair of electrodes, or alternatively a combination electrode, and some form of display calibrated in pH units. It usually has a glass electrode and a reference electrode, or a combination electrode. The electrodes, or probes, are inserted into the solution to be tested.
Organic indicators are chemical species that change their colour in response to changes in the pH of the solution. This implies that the anionic and protonated forms of the indicator possess different colours. Hence the colour changes in acidic, basic and neutral solutions. The images attached indicate the colour changes in phenolphthalein and methyl orange in acidic and basic media accordingly.