Explain virtual image?

1024

---

Explain what is the opaque?

1078

---

Explain what is the transparent?

1018

---

Tell me why ship doesnt sink sea?

1153

---

Explain what is the ray of light?

1029

---

What are the stars?

905

---

What is solar eclipse?

921

---

Explain the planets?

987

---

What is eclipses?

944

---

Explain shape of the earth?

888

---

What is astronomical telescope?

977

---

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

906

---

What is lunar eclipse?

927

---

Explain the moon?

952

---

What is equatorial and polar diameter?

917

---