Answer:
HCl, Option A.
Explanation:
Hcl is a strong acid, NaOH is a strong base, the saliva has a relatively neutral pH and blood is slightly acidic.
Answer:
halve the slit separation
Explanation:
As we know that
In YDS experiment, the equation of fringe width is as follows

where,
D denotes the separation in the middle of screen and slits
d denotes the distance in the middle of two slits
And to increase the Δx we have to decrease the d i.e, the distance between the two slits
Hence, the first option is correct
Answer:
0.25 m/s
Explanation:
This problem can be solved by using the law of conservation of momentum - the total momentum of the squid-water system must be conserved.
Initially, the squid and the water are at rest, so the total momentum is zero:

After the squid ejects the water, the total momentum is

where
is the mass of the squid
is the velocity of the squid
is the mass of the water
is the velocity of the water
Due to the conservation of momentum,

so

so we can find the final velocity of the squid:

and the negative sign means the direction is opposite to that of the water.
Answer:
Solid cylinder
Explanation:
because hollow may blow and just bounce
When undergoing an ultrasound, the transducer probe of the ultrasound machine transmits sound waves. It also receives the sound waves that are reflected back after it reaches a boundary.
The reflected waves are received by the probe and relayed to the ultrasound machine. The machine calculates the distance from the probe to the tissue or organ (boundaries) using the speed of sound in tissue and the time of the each echo's return. It then <span>displays the distances and intensities of the echoes on the display screen, forming a two dimensional image. </span>