Explain virtual image?

979

---

Explain what is the opaque?

1030

---

Explain what is the transparent?

974

---

Tell me why ship doesnt sink sea?

1087

---

Explain what is the ray of light?

989

---

What are the stars?

844

---

What is solar eclipse?

883

---

Explain the planets?

943

---

What is eclipses?

895

---

Explain shape of the earth?

845

---

What is astronomical telescope?

936

---

What is the distance of the earth from the moon and the sun?

862

---

What is lunar eclipse?

888

---

Explain the moon?

909

---

What is equatorial and polar diameter?

867

---