Answer: 7,000 ohms
Explanation:
From the equation of ohms law V= IR
V=21 volt
I = 3 MA = 3.0×10^-3 A
So by evaluating, we have.
V= IR
21= 3.0×10^-3 × R
Then R = 21/3.0×10^-3
R= 7,000 ohms//.
Answer:15,883.63 KJ
Explanation:
Given
Power=400 W
Freezing compartment temperature is 273 K
Outside air Temperature=306 K
Time =80 minutes
Energy Required to deliver 400 w power in 80 minutes
E=1920 KJ
and we know COP of refrigerator is given by




Therefore 15,883.63 KJ is removed in 80 minutes
Answer: 1,500m/s
Explanation:
Relationship existing between velocity of a wave (v), wavelength(¶) and frequency(f) is
v = f¶... (1)
Since Frequency (f) is the reciprocal of the period (T);
Frequency = 1/Period i.e F = 1/T... (2)
Substituting equation 2 into 1 we have;
v = 1/T × ¶
v = ¶/T
Given wavelength ¶ = 9m
Period T = 0.006s
v = 9/0.006
v = 1,500m/s
The velocity of the wave will be 1,500m/s
Answer:
4.has gained two electrons
Explanation:
There exist electrovalent bonding the compound MgS . In electrovalent bonding, there is a transfer of electrons from the metal to non-metal.
Magnesium atom has an atomic number 12 and its electron configuration is 2,8,2
Sulfur atom , a non-metal has atomic number of 16 and its electron configuration = 2,8,6
This means that magnesium as a metal needs to loose two electrons from its valence shell to attain its stable structure.Also sulfur requires two more electron to achieve its octet structure.
Hence a transfer of electrons will take place from magnesium atom to sulfur atom, sulfur gaining two electrons.